CHICAGO (CBS) — Detectives in Kankakee County were investigating four homicides over the weekend in rural Pembroke Township, including a triple homicide Sunday afternoon, and police believe the slayings are connected.

Just before 1 p.m. Sunday, police found the bodies of 56-year-old Reginald Neal and his two sons — 24-year-old Dangelo Neal and 21-year-old Davante Hopkins — inside a home on the 4300 block of South 15500E Road. All three had been shot. A family member had discovered the bodies and called police.

Those homicides followed the shooting death of a man who was found about around 1 a.m. Saturday in the driveway of a home at 6624 South 17250E Road, not far from Neal’s home. Kankakee County Coroner Robert Gessner said 46-year-old Ralph Ledet was shot in the head more than once.

Police said all four victims lived together. Kankakee County Sheriff Mike Downey said the problem is detectives don’t yet know why the four people were killed.

“The only criminal contact that we found at that address has been some domestic calls,” he said.

The sheriff said the killings do not appear to be random.

“There’s obviously someone on the loose, so yeah that’s a concern. However, we think this was something that was targeted,” he said.

Downey said investigators are looking at everything from the Sunday victims being involved in the Saturday killing to everything else.

The sheriff also said there were dogs of different breeds found in the house on Sunday and removed and put in the car of family, but Downey did not know if someone had been selling dogs out of the house.

Kankakee County Crime Stoppers is offering a $1,000 reward for information leading to the killer or killers.