HAMMOND | Police are again warning residents to beware of scam artists posing as workers for NIPSCO, the Water Department or other utilities after an incident Thursday, which brings the total to five since March 3.

In at least three of the five reported incidents, men masquerading as utility workers have gotten into homes by telling residents they needed to check the furnace or turn off the water, police Lt. Richard Hoyda said Thursday.

Hoyda said the March crimes are the latest of about 25 since Dec. 5. Many appear to target homes with elderly residents.

"We don't want anybody letting down their guard," he said.

In the latest crimes, Hoyda said a man on March 14 described as white with gray hair and a full beard knocked on the door of a house in the 4100 block of Sheffield Avenue, saying he was with NIPSCO and needed to check the furnace.

The homeowner called the utility and learned there were no NIPSCO workers in the area. The imposter was reported leaving the area in a white, late-1990s Ford van similar in appearance to a NIPSCO van and marked with NIPSCO lettering.

Hoyda said two incidents occurred March 19 -- one in the 4300 block of Henry Street and the other in the 1800 block of 169th Street.

One of those incidents involved two white men in work jackets coming to a resident's door, saying they were from the Water Department and needed to turn off the water to the whole block, Hoyda said. The men offered the homeowner a $20 rebate for turning off her water. After entering the house, the men reportedly drove off in a newer model black car with possible Illinois license plates.

In the other incident, two men, one white and the other black, forced their way into the home and rummaged through dresser drawers before leaving in a newer model white four-door car, he said.

On Monday, Hoyda said, a heavy-built Hispanic man came to a door in the 1700 block of 171st Street, saying he was with the Water Department, needed to check the water and required $70. He was joined by another Hispanic man. The men were reported fleeing in a silver four-door car after entering the home.

The most recent incident occurred Thursday in the 1600 block of Parkview Avenue in Hammond's Robertsdale neighborhood, Hoyda said. Two men, described as Hispanic, entered a home through a door that had been left open in anticipation of a doctor's visit.

The smaller of the men told the female resident he and his associate were there to repair the sidewalk in front of her house and pushed her wheelchair to the window while talking about the work, the resident told police.

While her back was turned, the larger man went into her bedroom and took a safe that held various personal papers and an envelope containing cash, the resident said.

The men were described as having dark hair and eyes, with one measuring 5 feet 5 inches with a slim build, and the other taller than six feet with a large build.

Police are reminding residents that all city employees and utility workers carry official identification and will show it on demand, and they recommend calling 911 if a suspicious person comes to the door.

The Hammond Police Department's Web site, HammondPolice.com, features a map which tracks reported attacks by the thieves over the past 16 weeks.

Anyone with information about the robbers is asked to call Detective Michael Daniels at (219) 852-2961 or Detective Steve Guernsey at (219) 852-2978.

Correspondent Steve Zabroski contributed to this report.