Twenty-one Long Island bank robberies have occurred since Jan. 1, an uptick that has local police officials concerned.
The 14 robberies in November represent the next highest total in the past 13 months, records show.
Police in Nassau and Suffolk counties attribute the rash of robberies to several thieves committing multiple heists and a preholiday spike.
Twelve bank robberies have been committed in Suffolk since Jan. 1 and nine in Nassau. Since November, police in both counties have reported 46 robberies -- 29 in Nassau and 17 in Suffolk.
With already a dozen this month, Suffolk is poised to shatter last year's total of 19, statistics show.
"We have concerns. . . . It's only January and we have 12 cases," said Det. Lt. Edward P. Reilly, commanding officer of Suffolk's Special Investigations Section. "Whether that's a one-month uptick or a prolonged increase is yet to be determined."
No injuries have been reported during the robberies, though some of the suspects had guns. Both counties declined to say how much was taken in each robbery.
In response to the increase, Nassau police say they've deployed both patrol and plainclothes officers to areas that might be targeted. Suffolk declined to specify its tactics.
"We're trying to anticipate the subjects and their activity and we will flood that area with our presence," said Det. Sgt. John Giambrone, the commanding officer of Nassau police's Robbery Squad.
Nassau police have made arrests in four of this month's nine robberies. Giambrone said they expect to soon arrest two men they believe are working together and have committed five of the month's unsolved robberies -- including one Tuesday night of a Chase Bank in Farmingdale.
Giambrone said the FBI has issued a warrant for another suspect, currently in drug rehabilitation. Police say that person has committed six robberies in Nassau -- three cases from 2012 and three from 2013. Nassau police work with the FBI "on a regular basis" to solve bank robbery cases, he said.
Robert Davidson, 56, of Uniondale, a parolee who has been charged with three counts of third-degree robbery, was arrested in connection with a string of January bank robberies in Nassau. Police said he presented a demand note to a teller at a TD Bank on Merrick Road in Rockville Centre about 2:15 p.m. Jan. 10. Three days later, police allege, he went to a Capital One Bank on Merrick Road in Merrick, presented a note and made off with an undisclosed amount of cash. About four hours later, police said, he did the same thing at a TD Bank in Garden City.
Davidson, who police said wore a Toronto Blue Jays baseball cap during two of the heists, was arrested 10 days later. The baseball cap helped crack the case, police said.
Both department officials said it's difficult to pinpoint the reason for the increase, but said several of the robberies appear to be the work of a single assailant, which has helped spike the numbers. In Nassau, officials said the 20 robberies in the last two months of 2013 could be attributed, in part, to a push for cash around the holiday season, when officials say robberies of all kinds generally increase.
Suffolk detectives have solved four of the 12 cases they've investigated this month -- including arresting one suspect who has allegedly committed three bank robberies, in Babylon, Brentwood and West Islip, Reilly said.
"We have a number of leads," he said of the remaining unsolved cases. "We can't say there's a definable pattern on those cases."
Giambrone, who has commanded Nassau's robbery unit for nine years, said generally people who commit bank robberies "have some sort of addiction" -- alcohol, drugs or gambling and oftentimes do it more than once.
Bank robberies and attempted robberies on the Island have mostly been on the decline since 2008, when Nassau police documented 85. In Nassau, that number was cut by more than half to 40 in 2009, and it fell to 27 in 2012.
In Suffolk, there were 52 robberies in 2008. Following two years of declines, the number shot back up to 37 in 2011.
An increase in bank robberies can't be directly attributed to economic conditions, said Robert McCrie, a security management professor at John Jay College of Criminal Justice, who has studied bank robberies for more than 40 years.
Though Nassau and Suffolk's totals were high for 2008 -- the height of the country's economic downturn -- bank robbery numbers nationally were on the decline then, McCrie said.
"It's a crime of impulsiveness," McCrie said. "Robbers have been trained in the assumption that if they go into a bank and pass a note, they're going to come away with some money. Maybe not as much as they want, but they'll get immediate cash."
McCrie said the amount of cash a thief can net from a bank heist has decreased substantially in recent years as banks have stepped up security measures, including keeping less cash in teller drawers. All banks are equipped with video monitoring per federal law, McCrie said, which helps police in identifying suspects.
Both departments say they provide training to local bank employees on what to do if a thief approaches them.
"It's for them to understand how to be the best witness and how to act during the robbery," Giambrone said."We tell them to comply with company policy and do what the subject tells you to do."