Authorities discovered an American couple carrying a dead toddler in a duffel bag while trying to walk across the border into Mexico.

Mexican border officials stopped the couple on Tuesday, according to San Diego Police Department's Lt. Ray Valentin. The couple attempted to cross into Tijuana around 11:30 a.m. PT via the pedestrian border crossing at the San Ysidro port of entry.

The man was carrying a bag.

Officials scanned the man’s bag using an X-ray machine and discovered the body of the small girl inside the bag. According to Valentin, the child was approximately two years old.

Valentin said the man's companion tried to run away, but she was quickly apprehended and taken into custody. The man was also arrested.

Mexican officials deported the couple back to the United States. According to Valentin, the pair are residents of Whittier, California.

The SDPD Homicide Unit is now leading the case. On Wednesday afternoon the SDPD identified the man and woman as Johnny Lewis Hartley, 39, and Mercy Mary Becerra, 43, both of Whittier.

Both Hartley and Becerra were booked into jail in San Diego and are facing counts of first-degree murder and child cruelty. They are both scheduled to appear in court Friday.

At this point, it is unclear if the couple has retained an attorney.

After interviewing the suspects, SDPD Homicide Unit detectives have determined that whatever happened to the girl may have occurred in Whittier. The SDPD is now working closely with detectives of the Whittier Police Department.

Valentin said Hartley and Becerra are not the toddler's parents but investigators believe they knew her and her parents prior to her death. He says that organ trafficking is not a factor in this case.

The toddler's parents live in the Whittier/Greater Los Angeles area.

NBC 4 Los Angeles confirmed Becerra's Instagram account; her bio on the social media page says she's a mother of nine.

The San Diego County Medical Examiner's office took custody of the toddler's body and will determine the cause and manner of the girl's death.

No further details were immediately available. The investigation is ongoing and anyone with information on the case can call the SDPD Homicide Unit at (619) 531-2293 or Crime Stoppers at (888) 580-8477.

Whittier is located approximately 127 miles north of Tijuana.

This is a developing story. Check back for updates.