SAN DIEGO — The family of a Mexican migrant who died in custody of U.S. Border Patrol last year is suing the federal government for negligence, alleging that the man was denied medical care for fatal injuries sustained during a fall from the Otay Mesa border wall.

Joel Reyes Muñoz, 38, died shortly before 3:30 p.m. on Jan. 12, while in custody at the Otay Mesa Port of Entry. He was undocumented at the time of his death.

In a report the following day, San Diego police said Reyes Muñoz, who had not yet been identified, was stricken by some sort of medical emergency as he was waiting for processing in Customs and Border Patrol custody.

However, the complaint, which was filed with the court last Aug. 3 by Reyes Muñoz’s family, alleges that he had sustained “obvious and significant blunt force injuries” in a fall from the high U.S.-Mexico Border barrier prior to his arrest just north of the fence.

“At the time of the initial apprehension of (Reyes Muñoz), it was apparent to (agents) that he had fallen, that he was injured, and that his condition was grave,” his family says in the complaint.

Despite these injuries, he went untreated until he became unconscious and stopped breathing, the complaint says. At that point, Reyes Muñoz’s family alleges emergency medical personnel were finally summoned.

By the time medical personnel arrived, however, his family said it was too late for Reyes Muñoz. The Border Patrol’s delayed response to his injuries, the complaint alleges, cost him his life.

CBP declined to comment on the pending litigation after FOX 5 sent a request for a statement.

Leticia Duran Martinez and her two sons, representing the estate of Reyes Muñoz, are accusing the U.S. government and unnamed federal agents of negligence, wrongful death and a violation of the Bane Act — a California civil rights law that forbids people from interfering with a person’s constitutional rights by force, threat or violence.

In this case, the complaint argues Bane Act prohibits “deliberately indifferent failure or refusal to render medical (care) for a serious medical need.” While holding Duran Martinez’s late husband in custody, the complaint alleges Border Patrol agents did just that in their delayed response to his injuries.

Reyes Muñoz’s death also came at a time when border fall injuries were skyrocketing, due to a raising of the barrier’s height from between eight to 17 feet to a height of 30 feet — a pattern of which his family says federal agents were aware.

According to the complaint, a study from the American Medical Association Surgery Journal found that the UC San Diego Trauma Center, which treats patients who fell from the border wall, saw a five-fold increase in people admitted for such injuries.

“(Border patrol agents) had a duty to Mr. Joel Reyes Muñoz to act with care and prudence so as not to cause harm or injury to him,” the complaint reads. “(The agents’) actions fell below the standard of care and breached their duty of care to decedent.”

The lawsuit is seeking an undetermined amount of compensatory general and special damages for the death of Reyes Muñoz. Preliminary hearings for the civil case have not yet been set.