On March 7, Mohan robbed the Salem Five Bank branch in Tewksbury, Mass., handing the teller a note claiming someone was watching the building and walked out with a bag of cash containing $8,000.

Twelve days later on March 19, Mohan was speaking about loans for about 15 minutes with the manager at the Danvers, Mass., branch of the $697 million Align Credit Union when he handed the manager a note requesting "all the money," according to Mohan's plea agreement. He walked out of the branch with $7,613.

On March 29, he handed a note to a teller at the Lee, N.H., branch of the $2 billion Northeast Credit Union that said he was robbing the credit union, was armed and had no problem harming the teller, court documents showed. He left the branch with $6,000.

The next day, on March 30, he walked into the same branch of Salem Five Bank in Tewksbury that he robbed on March 7, handed the teller a black plastic bag and said, "You know the drill." He claimed to have a firearm and walked away with $2,000.

But Mohan's luck ran out on April 4, when FBI agents were tailing his car, which had been identified as a vehicle of interest caught on security cameras from prior robberies he committed.

FBI agents saw Mohan put gloves on before he entered the Hampton, N.H., branch of the $5.1 billion Service Federal Credit Union. He handed a demand note to two tellers and walked out with more than $10,000.

Following his arrest, Mohan admitted to the string of robberies.

In his sentencing memo to Judge McCafferty, Mohan described his addiction to drugs that began when he was a teenager and how he also developed a gambling addition to support his substance abuse issues.

At times, throughout his life, he managed to maintain sobriety that enabled him to hold steady jobs as a kindergarten teacher in Massachusetts. He also worked as an executive director of a learning center that assisted individuals with disabilities in developing their maximum potential and independence.

At age 46, however, he relapsed on Percocet, and within a matter of months he was on heroin. He was consuming about five grams of heroin a day up to his April 4 arrest following the Service robbery, according to court documents.