A man suspected of shooting and killing eight people in suburban Chicago is believed to have fatally shot himself after a confrontation with law enforcement officials in Texas, police said.

Police in Joliet, Illinois, said on Facebook that at about 8.30pm local time on Monday 23-year-old Romeo Nance was located by US Marshals near Natalia, Texas, and that Nance shot himself after a confrontation.

The Medina County Sheriff’s Office in Texas said on Facebook that the agency received a call about a person suspected in the Chicago-area killings heading into the county on Interstate 35. A standoff then occurred between Nance and police from multiple agencies at a petrol station, where Nance shot himself, the sheriff’s office said.

Nance is suspected of fatally shooting eight people at three locations in the Chicago suburbs, sparking a search that left neighbours on edge earlier on Monday as police warned he was still on the loose and should be considered “armed and dangerous”.

Police in Will County in Illinois and Joliet previously said they did not know of a motive for the killings, but said Nance knew the victims.

The FBI’s fugitive task force had been assisting local police in the search for the suspect, Joliet Police Chief William Evans said.

The victims were found on Sunday and Monday at three separate residences, authorities told reporters at a news conference earlier on Monday evening.

One of the people killed was found with an apparent gunshot wound on Sunday outside apartments in Will County and pronounced dead at a hospital. He was identified by the Will County Sheriff’s Office as a 28-year-old man originally from Nigeria who had been living in the US for about three years.

Seven others were found on Monday at two homes on the same block in Joliet, located about about six miles (9.6km) northwest of the scene police discovered first.

Authorities said they also believe Nance was connected to another shooting in Joliet that wounded a man on Sunday but would not discuss their evidence.

“I’ve been a policeman 29 years and this is probably the worst crime scene I’ve ever been associated with,” Mr Evans said during a news conference outside the Joliet homes on Monday evening.

Will County Chief Deputy Dan Jungles said during the Monday news conference that deputies had been staking out one of the houses since Sunday evening in case Nance, the suspect in the first fatal shooting they discovered, returned to them.

Nance’s last known address was one of the homes, police said.

When no-one showed, deputies finally went to the door of one of the houses. No-one answered so they crossed the street to the other house, which they knew was linked to the first house and found the first bodies. Five bodies were found in one house and two bodies were found in the other.

Mr Jungles said he did not have any indication yet of how long the people in the houses had been dead. He said that autopsies were pending.

Mr Evans said the victims found on Monday in the houses were family members. Asked if the victims were members of the suspect’s family, Mr Jungles said he could not comment except to say that the suspect knew them.