Nassau County police charged a man with murder in the “targeted” killings of his mother, sister and a third woman in Hempstead, officials said Saturday.

Police said Bobby Vanderhall, 34, was arrested on three charges of murder in the early morning deaths of his mother, Lynn Reichenbach-Vanderhall; his sister, Melissa Vanderhall; and Janel Simpson, who family members say was visiting the home.

Police said the three women were found dead from “blunt force trauma” at a home on Perry Street about 2:15 a.m. A Nassau County police medic pronounced them dead at the scene.

A fourth woman who was assaulted fled the scene and flagged down a passer-by who called Hempstead police, authorities said.

The woman, who has not been identified, remained hospitalized to be treated for wounds from the attack. Bobby Vanderhall faces a charge of attempted murder in that assault, police said.

Lt. Stephen Fitzpatrick, commanding officer of the Homicide Squad, described Bobby Vanderhall as a “physically imposing person,” at more than 6 feet tall and 230 pounds.

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Fitzpatrick said he had become homeless because his mother recently kicked him out of the house.

“When he came here last night and it looked like the doors were secured, he became enraged,” he said. “He went to the garage. He obtained a large hammer. . . . With this framing hammer, he broke through the basement door.”

Police said Bobby Vanderhall then found his mother in the living room and started to strike her with the hammer.

“The girls were all upstairs and heard what was going on in the living room,” Fitzpatrick said. “As they came to the staircase, Bobby was already coming up after them.”

He assaulted the fourth woman — who later got away — and struck his sister on the head, Fitzpatrick said. Bobby Vanderhall proceeded to find Simpson in another room and also attacked her.

Police said he stayed in the home briefly after the attack and was later found sleeping in a parked vehicle.

Bobby Vanderhall had a history of “emotional issues” and had on two occasions been taken from his mother’s home to a medical center, Fitzpatrick said.

Officials do not know his diagnosis but said his behavior had become more “unruly” recently, leading his mother to obtain an order of protection against him.

“He became more violent,” Fitzpatrick said. “His mother had enough.”

In one instance, Bobby Vanderhall called police because his mother withheld his social services money. In another, his mother accused him of slapping and harassing her, Fitzpatrick said.

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Bobby Vanderhall had been convicted of sexual abuse and forcible touching of a female in 2015, and possession of a controlled substance in 2007.

Lynn Reichenbach-Vanderhall, 58, was a happy, loving person who was devoted to her children, said a niece, Juanita Johnson.

“She did anything for anyone,” Johnson said. “Both her kids were her world.”

Reichenbach-Vanderhall worked as coordinator of the Family and Children’s Association’s nursery co-op in Hempstead.

Melissa Vanderhall, 29, and Simpson both were graduates of Uniondale High School, where Vanderhall played volleyball.

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Denis Simpson, who went to the scene Saturday morning, identified himself as the father of Janel Simpson, 29, who had gone to the home to visit friends.

“That’s my one daughter,” the man said, of learning she had died. “I can’t take it.”

Wendy Simpson, Janel’s mother, said her daughter had worked until 11 p.m. Friday before going to visit the Vanderhalls and was planning to work at 8 a.m. Saturday. Simpson had cooked food for her to take to work that morning.

“She was a good daughter. I was up at 4 in the morning cooking for my Janel and the plate is in the fridge, waiting for her,” Wendy Simpson said. The family lives in Uniondale.

The police department’s Homicide Squad is investigating.

Vanderhall will be arraigned Sunday in First District Court in Hempstead.

With Mark Morales, Valerie Bauman and Howard Schnapp

CORRECTION: An earlier version of this story incorrectly stated where Bobby Vanderhall was found; he was found sleeping in a parked vehicle.