A Dallas police officer was arrested and charged with two counts of capital murder, according to the Dallas Police Department.
Officer Bryan Riser, 36, was taken into custody Thursday morning, DPD Chief Eddie Garcia said at a press conference.
Riser is charged in the murders of Lisa Saenz, who was found shot dead in the Trinity River in March 2017, and of Aubrey Douglas, who was reported missing in Feb. 2017 but whose body was never found.
"We received information from a witness that implicated Riser in both murders," Garcia said. "The motive for these murders is unknown at this time, and this remains an ongoing investigation."
Garcia said the two murders were connected to Riser's "off-duty" life, but added "we will be looking at the activity he conducted as a police officer," including his arrest record.
Riser joined DPD in Aug. 2008 and has since been assigned to the South-Central Patrol Division, which includes the address near the Trinity River in Dallas where the murders are believed to have occurred, according to the affidavit for arrest warrant.
Three men were arrested and charged in connection with Lisa Saenz's murder in 2017, NBC Dallas-Fort Worth reported, but none of them have been to trial and court records show murder charges against them are still pending.
The affidavit posted Thursday afternoon says Riser paid thousands of dollars to one of the three people who was arrested for Saenz's murder in 2017.
Also in 2017, Riser was placed on administrative leave and investigated because of a domestic violence misdemeanor charge, according to the Dallas Morning News.
DPD spokesperson Officer Melinda Gutierrez told NBC News on Thursday that Riser was back on active duty when he was arrested, but declined to say when he was reinstated after the 2017 investigation.
Riser was first implicated in the murders in Aug. 2019, Garcia said, which is when a witness told the Dallas Police Department that they kidnapped and killed a person at Riser's direction.
The affidavit says the FBI provided cell tower data linking Riser to the scene in Oct. 2019.
"We will hold ourselves accountable to the highest levels," Garcia said. "Although he is in custody, he is on administrative leave pending the outcome of an Internal Affairs administrative investigation."
Brian Mayes, a Dallas police union spokesperson, declined to comment and could not say whether Riser has an attorney.