The fourth victim to be shot dead in a Florida neighborhood in a possible serial killing spree was an unemployed construction worker who volunteered at a food bank.

The Tampa Bay Times reports that 60-year-old Ronald Felton volunteered several times a week at a Seminole Heights food bank near where he was gunned down just before 5 a.m. Tuesday, possibly by a serial killer.

Cynthia Murray told the newspaper Felton had been living with her and would often arrive at the food bank at 2:30 a.m. to help.

Police have sealed off the neighborhood and were searching for the suspect. They say the gunman walked up behind Felton as he crossed a street and fired.

Three people were slain in Seminole Heights last month in a 10-day span. All three were alone and had gotten off a bus when they were gunned downed at night for no apparent reason. None was robbed.