The Police commenced a manhunt after multiple shootings left eight people dead in Illinois, police say.
Police found the bodies of seven people on Monday in two houses in the city of Joliet, near Chicago. The victims were all believed to be part of the same family, authorities said.
Two separate shootings, one lethal, were also reported to police on Sunday.
Police are seeking Romeo Nance, aged 23, and warn that he “should be regarded as armed and dangerous”.
Investigators in Joliet, Will County, said Mr Nance was believed to be driving a red Toyota Camry. They urged anyone with information about the attack, 40 miles (64km) south-west of Chicago, to contact them.
“This is an active investigation in which we are working with our area law enforcement partners,” Joliet police department said in a statement.
Joliet police chief Bill Evans told a news briefing that police were notified at 12:04 local time (18:04 GMT) on Monday that several people had been found shot dead.
After arriving at the scene on West Acres Road, officers discovered seven bodies. Five were found in one house, and two in the other, Will County Sheriff’s deputy chief Dan Jungles said.
“I’ve been a policeman 25 years. This is probably the worst crime scene I’ve ever been associated with,” Mr Jungles said.
The motive for the attack was not immediately clear, but the suspect is believed to have known the victims.
Separately, authorities said they had been notified of two shootings a day earlier at different locations in Joliet.
They said a car with the same number plate as the one linked to the discovery of the seven bodies on Monday was spotted in both locations.
One of the shootings resulted in the death of a 28-year-old man, who was shot in the head, authorities said.
He was identified by police as Toyosi Bakare, who was originally from Nigeria and had been living in the US for the past three years.
Police said a 42-year-old man was shot in the leg at a separate location earlier that day, resulting in non-life threatening injuries.
