A robbery demand note led to an arrest Thursday after a man's son mistakenly handed it to police.

When a police officer asked for identification, the note was inadvertently presented, police reported.The same note had been used during two recent robberies at an east-side Smith's Food and Drug Center.

Police, who stopped the man because he looked suspicious, began questioning the man at 6:30 p.m. after he and two juveniles entered a covered parking lot at 600 E. 200 South.

Salt Lake Police Lt. Mark Zelig said Sgt. Arthur Healey arrested the suspect, 28, when the officer received the note and suspected the man was wanted in connection with the robberies at the Smith's supermarket on 876 E. 800 South.

The man's son was also carrying a knife, police said. The juveniles were released, Zelig said.

About 3:30 p.m. Monday, a man wielding a sawed-off shotgun entered the supermarket and demanded, through a robbery note, money from both a service booth and a clerk at a cash register. He then escaped with an undetermined amount of cash.

Wednesday night, a man matching the same description robbed the same grocery store about 7:30 p.m. and fled with a considerable amount of cash. In that robbery, he had apparently hidden a shotgun inside the sleeve of a jacket.

"It's ironic that the thing he used to commit the crimes served to arrest him," Zelig said.