DALLAS: A Dallas police officer was arrested Thursday on two counts of capital murder, more than a year and a half after a man told investigators that he kidnapped and killed two people at the officer's instruction in 2017, authorities said.

Bryan Riser, a 13-year veteran of the force, was arrested Thursday morning and taken to the Dallas County Jail for processing, according to a statement from the police department. A lawyer for him couldn't immediately be identified.

Riser was arrested in the unconnected killings of Liza Saenz, 31, and Albert Douglas, 61, after a man came forward in August 2019 and told police he had kidnapped and killed them at Riser's direction, police Chief Eddie Garcia said during a news conference. He said investigators don't know the motives for the killings, but that they were not related to Riser's police work.

Garcia did not explain why Riser was arrested nearly 20 months after the witness came forward, and police did not immediately respond to questions about the timing. Riser joined the department in 2008, and Garcia acknowledged that he had been patrolling Dallas while under investigation for the killings.

The chief stressed that his homicide division and the FBI were still investigating the killings and said the department was reviewing Riser's arrests.

Saenz’s body was pulled from the Trinity River in southwest Dallas on March 10, 2017, with several bullet wounds, the chief said. Douglas was reported missing that year and his body hasn’t been found.

Three people were previously arrested and charged with capital murder in Saenz’s killing, according to an affidavit for Riser's arrest. It does not identify any of them by name.

One of them allegedly told police that he and Riser were involved in burglaries when they were young. They more recently hatched a plan to rob drug stash houses, but they didn't follow through with it, according to the affidavit.

Instead, the man told investigators that Riser offered to pay him a total of $9,500 to kidnap and kill Douglas and later Saenz. Both were shot and their bodies were dumped in the river, according to the court record.

The affidavit states that Riser told the hired killer Saenz was an “informant.” The document does not elaborate, and police did not immediately respond to questions about whether Saenz had some connection to the department.

The murder charges are not the officer's first alleged crimes. In May 2017, Riser faced a domestic violence charge for allegedly assaulting and injuring an ex-girlfriend. It wasn't immediately clear how that case was resolved, and Garcia declined to comment on it Thursday.

Riser has been put on administrative leave pending the outcome of an internal affairs investigation. Garcia said “we’re going to expedite our process” toward his firing.

“We will not allow anyone to tarnish this badge," the chief said.

Riser had not been booked into the jail as of early Thursday afternoon, a sheriff’s spokesman said.

A spokeswoman for the Dallas County district attorney’s office said her office didn’t have information on the case.