Officer Bryan Riser, a 12-year veteran in the department, faces two counts of manslaughter, the chief announced at a news conference.
“This criminal investigation dates back to 2017, with the death of two unrelated murder victims,” said García.
The victims are identified as Lisa Saenz – whose body was found in a river after being shot dead, says the arrest statement – and Albert Douglas, whose body was never found, according to García.
The police chief said Riser had “a relationship” with at least one victim, but did not expand the relationship and said the reason for the separate murders was unknown.
An arrest statement says Riser referred to Saenz as an “informant”.
“We will not allow anyone to wear this badge,” said García, who served as head of the Dallas Police Department for just a month.
Riser did not respond to CNN’s attempts to contact him by email. It is not clear whether he has legal representation.
CNN’s request to comment the matter to the local police union, the Dallas Police Association, was referred to a public relations firm, which declined to comment.
The chief said that Riser joined the department in August 2008 and, more recently, has served as a mid-south patrol officer. García added that he will review all of Riser’s previous arrests to ensure that there is no misconduct involved.
Three other people have also been charged with capital murder in connection with the murders, but the statement does not reveal their identities or the status of their cases.
Under the terms of the department’s collective bargaining agreement, Riser remains in force while an internal affairs investigation is carried out, the chief said. “We are conducting an administrative investigation as soon as possible, towards termination,” added García.
Garcia thanked the FBI for its assistance in the ongoing criminal investigation.
Online prison records list the value of Riser’s bail at $ 5 million. He is being held at the Torre Norte Detention Center, records indicate.
CNN’s Steve Almasy contributed to this report.