Luis Ramirez and his wife, Andrea Ramirez, may have fled to Mexico with their children.

A Tucson couple accused of kidnapping their kids by using a stun gun on a child welfare worker are suspected of being involved with child pornography, and each faces more than two-dozen sex-crime charges, court records show.

Luis Ramirez, 30, and his wife, Andrea Ramirez, 28, have been under investigation since late 2016, when police searched their house and car for “pornographic materials” and seized cellphones, thumb drives, computer tablets and digital images, records show.

The sex-crime charges do not involve the couple’s children, a 5-year-old boy and 6-month-old girl kidnapped May 4 during what was supposed to be a supervised visit at a Tucson park. A contract worker with Arizona’s Department of Child Safety, assigned to supervise the visit, was disabled with a Taser and tied to a tree with duct tape during the kidnapping, authorities said.

The parents’ car was later found abandoned in Nogales, Arizona, suggesting they may have fled to Mexico with their children.

Lt. Colin King of the Tucson Police Department said authorities remain optimistic the kidnapped children will be found and returned to Arizona.

“The likelihood is high,” he said in an interview.

He said TPD immediately reached out to the FBI, U.S. Customs and Border Protection and the U.S. Marshals Service, which has personnel in Mexico.

Mexican authorities also are cooperating and have activated their own missing child alert system similar to the Amber Alert system in the U.S., King said.

Court records aren’t specific about why the state took custody of the Ramirez children, but they offer a possible reason: Each parent faces a felony child-abuse charge for allegedly “having a loaded firearm within reach” of their son in late 2016 when the boy was 4.

In March 2017, not long after police searched the couple’s car and their rented house in the 2400 block of East Beverly Drive, Luis Ramirez was charged with seven felonies and his wife with four for sexual exploitation of a minor.

The victim in the 2017 charges is identified only as A.S., a girl under the age of 15 who was made to pose in sexual positions while the suspects allegedly exploited her by “recording, filming, photographing, developing or duplicating” her image.

The 2017 charges were scheduled for a jury trial later this month.

But a few days before the kidnapping, the couple was reindicted on more than a dozen new felony charges.

The 2018 indictment, which involves the same victim as in 2017, includes 20 counts of sexual exploitation of a minor in connection with a series of digital images retrieved by police.

It also accuses Luis Ramirez of exposing himself to the victim, of touching her private parts and having her touch his. The couple also is jointly accused of jeopardizing the girl’s health by giving her alcohol when the alleged sex crimes were occurring, records show.

The alleged incidents took place over a three-year period between 2013 and 2016, the indictment said.

Darren DaRonco, a DCS spokesman, said confidentiality laws prevent him from commenting on the Ramirez case specifically.

In general, though, he said parents charged with criminal acts — even sex crimes against children — “have a constitutional right to visit with their children while in DCS care until their parental rights are severed by the court.”

The agency is evaluating the May 4 kidnapping “to determine what occurred and to see if any changes can be made to improve the safety of children, employees and contractors,” he said.

Contact reporter Carol Ann Alaimo at 573-4138 or calaimo@tucson.com. On Twitter: @AZStarConsumer