ORLANDO, Fla. — Investigators were examining the bank records of the father of the gunman in the Orlando night club massacre, as prosecutors convened a federal grand jury to consider whether criminal charges should be brought, a source said.

The grand jury is expected to weigh evidence against the killer’s wife, a federal law enforcement source with knowledge of the probe said on Wednesday. Investigators are looking at her role in the days and weeks before the deadly attack on the Pulse nightclub in Orlando by her husband, gunman Omar Mateen, the source said.

The bank records of the father, Seddique Mir Mateen, will help the Federal Bureau of Investigators and overseas law enforcement determine, the source said, how he financially supported his son and other relatives before the rampage that left 49 people dead and 53 wounded at the gay-friendly club Sunday.

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No evidence has been uncovered suggesting the elder Mateen used any funds for illegal purposes, but officials are scrutinizing business records, tax filings, and overseas contacts to determine his income sources and how he spent money that he had solicited online, the source said.

Officials would not comment on whether any of Mateen’s family were targets of criminal investigations.

Mateen’s son, who was born in New Hyde Park and briefly lived in Flushing and Westbury, went into the night club and began firing just after 2 a.m. Sunday. An off-duty Orlando police officer heard shots from the front, and began exchanging gunfire with him, authorities said. Officials said 39 people were found dead in the club while others died in ambulances and on the street.

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Authorities are trying to reconstruct the movements of Omar Mateen, 29, of Fort Pierce, over the past several months, with a massive effort heavily focused on digital, video and electronic evidence that will show where he spent the last few days before he died in a gunfight with the Orlando Police SWAT team.

It was unclear how much Seddique Mateen knew about the federal investigation into his financial records as he spoke to a reporter from the doorway of his Port St. Lucie home on Wednesday.

Mateen said, “I’m sure the FBI is very professional people.”

One of the bank accounts being examined is held in Germany, the federal source said, and Seddique Mateen is believed to have solicited donations to it in an online video posted in 2013.

According to spokeswoman Barbara Huebner of the German federal police agency, they are looking into information that Omar Mateen had connections in Germany. She would not say what precisely they were looking for, who requested the inquiry or whether the father’s bank records were being examined.

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A news report said that the German investigators for the BKA (Bundeskriminalamt) were looking into a Dusseldorf bank account held by the shooter’s father. A report said that the father Seddique Mateen posted the bank information in a 2013 video asking for donations.

Rep. Peter King (R-Seaford) said knowledgeable sources had told him that the wife and other family members of Omar Mateen are being “seriously” looked at by investigators. “That would include the father,” he said.

Omar Mateen’s wife, Noor Zahi Salman, 30, of Fort Pierce, could face federal charges ranging from abetting a crime to conspiracy to commit an act of terrorism, the federal law enforcement official told Newsday. Salman may have known her husband planned to carry out the attack at the club, the source said, and had given him a ride there in the days before the mass shooting to examine its level of security.

Salman told investigators that she was also scared of her husband, and tried to convince him to abandon his plan to carry out an attack, the official said. She has said she urged him to not “hurt anybody” at the Pulse nightclub or any other locations, the official added.

FBI agents have visited Salman’s relatives in California, where she grew up, the official said. Salman was born in the United States, the official said.

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No one answered the phone at a number listed for the family’s home in Rodeo, California, on Wednesday.

At the Orlando club, Omar Mateen was armed with a Sig Sauer MCX Carbine assault rifle and a semi-automatic pistol, authorities have said.

The number of bullets he fired from the Sig Sauer remains undisclosed as investigators continue to collect cartridge casings and magazines that typically hold up to 30 rounds of ammunition.

Firing a .223-caliber cartridge, the high-velocity bullet can pass through brick walls and typical residential construction.

In a news conference Wednesday, Assistant Special Agent in Charge Ronald Hooper, heading the night club massacre investigation, asked the public for tips and for their patience.

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“We want to hear from you,” he said. “I ask you for your patience as we continue our work.”

The nightclub, Pulse, located on Orange Avenue, will remain closed while evidence teams collect every possible clue to what happened. Hundreds of witnesses already have been questioned, according to Hooper and other officials.

Hooper declined to discuss Mateen’s guns which have been taken for testing by the FBI at its Quantico, Virginia, crime laboratory.

Investigators did not disclose other details of the probe, such as whether explosives were found inside the nightclub. Mateen claimed in phone calls with police while he was trapped inside the club that he had four explosive vests to put on some of the hostages.

Hooper characterized the nightclub shooting as “an act of terrorism born out of hate.” He also said he was not aware at the present time of any credible terrorist threats to Florida or the United States.

Noting that Mateen picked Pulse because it was a gay nightclub, Hooper said the FBI would pursue anyone threatening the lesbian, gay, bi and transsexual communities.

The first police officers who confronted Mateen and all the SWAT team members who killed him after a 3-hour standoff have begun debriefing and individual counseling to deal with the horror they confronted Sunday, according to Police Chief John Mina.

“These are some of the toughest heroes I know,” Mona said. “Nothing can prepare you for what those men encountered.” Hooper declined to say if the FBI had been interviewing Mateen’s wife.

Besides examining the father’s bank records, investigators also are examining if the father’s views on homosexuality and Middle East conflicts may have influenced his son.

Seddique Mateen is a native of Afghanistan and is active in that country’s expatriate community, having provided political commentary online and on foreign-language TV programs.

In videos posted on his Facebook page, Mateen has falsely portrayed himself as Afghanistan’s president — the head of a nonexistent government in exile. In a video posted the day before the nightclub shooting, Mateen, decked out in a military uniform, “ordered” the arrest of a host of Afghanistan officials.

“I order national army, national police and intelligence department to immediately imprison Karzai, Ashraf Ghani, Zalmay Khalilzad, Atmar and Sayyaf,” Mateen said, referring to Afghan officials. “They are against our countrymen and against our homeland.”

In another video, posted after the attacks, Mateen said he was “deeply saddened and announce this to the people of America.” He also said: “God himself will punish those involved in homosexuality. It is not for people to decide.”

Earlier this week, however, Mateen told reporters that he believed homosexuals have the right to live as they wish.

“They have the freedom,” he said. “It’s the law in these United States.”

In other statements to the media, he has repeatedly condemned his son’s actions and called them an inexcusable act of terror.

Later on Wednesday, thousands of Floridians and visitors had gathered in Orlando for vigils in memory of the dead and in support of the wounded.

Hundreds more began showing up daily to donate blood to replenish supplies for the wounded who underwent surgery just three blocks from Pulse at Orlando Regional Medical Center, the region’s trauma center.

Some $3.6 million has been donated since Sunday to assist the survivors and the victims’ families, Orlando Mayor Buddy Dyer said at a news conference held a block from Pulse on South Orange Avenue.

Called the OneOrlando Fund, donations included $1 million from Walt Disney World, $500,000 from the Orlando Magic and the team’s owners, the DeVos family, and $500,000 from J.P. Morgan.

The city also opened the Orlando Family Assistance Center at the Camping World Stadium, formerly known as the Citrus Bowl.

The services that began Wednesday included counseling for victims and their families. Some of those services are help with funeral costs and airline transportation for victims’ families, many of whom live in Puerto Rico.

Orlando Mayor Buddy Dyer said the community was not going to let the nightclub shootings define the community.

“We’re going to let the reaction that we take which is love and compassion and unity define us,” Dyer said. “We’re not going to change who we are. We’re not going to stop embracing diversity....And if anything, it’s going to draw us closer together. And it’s going to make us realize that we here in Orlando have to be an example for the rest of the world.”