SOAP LAKE - Twin brothers sought in connection with a Thursday morning fatal shooting and double stabbing in Soap Lake were booked into Grant County Jail.

Alfredo L. Silva and Juan D. Silva, both 18, both from Soap Lake, turned themselves in to the Ephrata Police Department at around 3 p.m. Thursday, according to Grant County Sheriff Tom Jones.

Both were sought for murder in the second degree and two counts of assault in the first degree.

At around 1:30 a.m. Thursday police from several agencies responded to reports of shots fired at a home on Buttercup Street South in Soap Lake. There they found an 18-year-old Moses Lake man shot. He died while being airlifted to a Wenatchee hospital, according to Jones.

His identity was not released by the coroner's office as of Thursday evening.

An 18-year-old female and 19-year-old male, both from Moses Lake, received non-life-threatening knife wounds and were later released from Columbia Basin Hospital in Ephrata.

What sparked the incident is not yet clear, Jones said. He added he did not know how many people were at the residence at the time of the incident.

It does not appear to be a random act and the incident was isolated to one home, Jones said.

Washington State Patrol Crime Lab technicians gathered and processed evidence at the scene Thursday.

The Columbia Basin Investigative Team checked about 30 locations across the county and interviewed multiple witnesses throughout the day, Jones said.

The team includes detectives from the Grant County Sheriff's Office, Moses Lake Police Department, Washington State Patrol, Adams County Sheriff's Office, Othello Police Department, Quincy Police Department, Ephrata Police Department and the Washington Department of Fish and Wildlife.

Investigators are still looking into whether the incident was gang related, although Alfredo Silva claims gang ties on his Facebook page.

Anyone with information for detectives is asked to contact the Sheriff's Office at 509-754-2011 ext. 468, or send anonymous information to crimetips@co.grant.wa.us.