Police have doubled the reward for information leading to the arrested and conviction of a man who they call a professional scam artist who preys on the elderly.

Doorbell video from earlier this week shows the man who bilked an 81-year-old Oceanside woman out of $45,000 in total. Police have now linked him to multiple crimes that began in January 2018.

Investigators say they don't know the man's identity, but they say he's responsible for five different scams targeting seniors throughout Nassau, including in Great Neck, Roslyn, Farmingdale and two separate incidents in Oceanside.

In each case, police say the suspect would call the victim, telling the person that a member of their family was in trouble and needed money. Then, the scammer would show up at the victim's house to collect the cash.

Police say each person scammed was over age 70. The suspect made off with close to $90,000 in total.

Police released a picture of the car the suspect was driving -- a dark-colored Ford Fusion with livery license plates.

There's now a $10,000 reward for information that leads to the man's arrest. Anyone with information can call Crime Stoppers at 1-800-244-TIPS.