A relative of a man who was killed in a Tuesday shooting is in custody in connection with the investigation, Raymondville Police Chief Uvaldo Zamora said.

Mario Martinez was arrested "without incident" on Wednesday afternoon, according to a news release by the Willacy County Sheriff's Office. 

RELATED STORY: Raymondville police investigating fatal shooting

Martinez was previously identified as the suspect in the shooting death of Reynaldo Acosta. 

Zamora identified Acosta as Martinez's half-brother. Zamora previously said a motive for the shooting is not known. Martinez will be arraigned Thursday on a murder charge, Zamora added. 

The shooting happened at the 800 block of West Tampico Avenue Tuesday at around 7:45 p.m.

Martinez was arrested at around 3:15 p.m. at the 1200 block of N. 2nd Street in Raymondville on a robbery charge, the sheriff's office stated.

A second individual, identified as Arianna Lynn Guerra, was also arrested at the residence Martinez was hiding in. She faces charges of assault of a public servant, hindering apprehension or prosecution of a known felon and possession of a controlled substance, the release added.