Photo by phone assists police

“Because of his involvement [we were] able to solve a crime,’’ said Cambridge Police Commissioner Robert Haas. “He really took it to a step that I haven’t seen in a long, long time.’’

Yesterday, the Mass Most Wanted TIP Program rewarded Grigoryants with a $300 check at the Cambridge police station for his quick thinking and initiative.

After discreetly snapping the photo, Grigoryants, 22, who works at the Cambridge Innovation Center, showed it to a teller at the bank, who immediately recognized the man. The bank called police.

Cambridge police responded, spotted McWilliams in front of the bank on Broadway, and arrested him. Police said that McWilliams had a fake beard, a wig, and a fake gun at the time. He has been charged with armed and masked robbery in allegedly taking $2,600 from the Eastern Bank on July 7. McWilliams was also wanted on several warrants, police said.

Grigoryants said he was honored by the praise from police, but that what he did was instinctive. He said did not think the wigged man saw him take the photo, so he was not afraid.

Peter Malionek, regional fraud investigator for Eastern Bank, said workers at the bank had been shaken up by the July 7 robbery.

“Getting that photo and bringing it in was really a smart thing to do,’’ Malionek said.

Brock Parker can be reached at brock.globe@gmail.com.