Lafayette Parish investigators have arrested a fourth person in the Jan. 28 killing of Silas Tate on Bayou Tortue Road.

Courtney Weeks, 18, was arrested on one count of accessory after the fact to second-degree murder, John Babin, spokesman for the Sheriff’s Office, said in an email.

Weeks joins three other suspects, including 21-year-old Dillon Trahan, the man believed to have shot Tate. Tate, 25, died at an area hospital after being shot in the head at around 10 p.m. on Jan. 28.

Trahan’s father, 43-year-old Steven Trahan Sr., and his brother, 23-year-old Steve Trahan Jr., also were arrested in the shooting. Trahan Sr., who was jailed on an original count of accessory to second-degree murder, now remains in jail on one count of aggravated assault.

All three Trahans denied involvement in the shooting, which took place at their home at 429 Bayou Tortue Road, according to the arrest affidavit.

Witnesses placed the Trahans at the scene and told deputies the three men confronted Tate over a utility trailer, the affidavit states. The same witnesses told deputies they heard several gunshots coming from an area where Dillon Trahan was standing alone, then saw Tate fall to the ground, bleeding from the head, according to the affidavit.

Babin did not say Friday what role Weeks is suspected of playing in the killing.