It still wasn't clear Monday morning why a suspected sniper opened fire on at least one resident and police the day before near Arlington.

The gunman died after an hours-long SWAT standoff with Snohomish County deputies Sunday night, but the circumstances of his death were equally unclear.

The standoff began around 1:30 p.m. when police were called to the 2500 block of Jim Creek Road near Highway 530 after a report of a man shot in the leg. The man told deputies that the gunfire had come from a wooded area.

According to Steve Dittoe of Snohomish County Sheriff's Office, when deputies arrived at the scene, they were shot at by the gunman.  

A multi-agency response, including a SWAT team and officers from Mill Creek, Stanwood and Edmonds, ensued, and surrounding houses were evacuated. Those officers were also met with gunfire.

At one point, law enforcement officials said they thought they might be looking for two gunmen because of the sheer amount of shots fired, but it was later determined that only one gunman was responsible.

The Sheriff's Office said the man used a high-powered rifle and perhaps more than one type of weapon.

By 8:45 p.m., deputies reported that the suspect had been shot and killed, but it wasn't clear if he'd shot himself or if he was hit by gunfire from police. Officials continued to search the area until about 11:30 p.m.

None of the officers were injured.

The man who was shot in the leg is 27, and is expected to be OK, his wife told KIRO 7.

Investigators confirmed Monday that several residents' vehicles may have been struck by stray gunfire. The Snohomish County Multiple Agency Response Team asked anyone whose vehicle may have been hit to call their anonymous tip line at 425-388-3845.

Deputies were back at the scene of the shooting Monday morning.

The Snohomish County Medical Examiner's Office said an autopsy is planned for Tuesday, during which they'll attempt to confirm the shooter's identity.