A Prince George’s County man who originally claimed that three armed intruders killed his mother-in-law and broke his nose was convicted Friday of killing the woman himself.

After deliberating for about three hours, a Circuit Court jury in Upper Marlboro convicted Ranulfo Alejandro Vargas, 24, of second-degree murder in the stabbing death of Cristela Bermudez Leon, 39.

“Today’s jury entered a just verdict,” said State’s Attorney Angela D. Alsobrooks. “The defendant’s brutal stabbing of his mother-in-law and subsequent lies to cover up his vicious attack were part of our strong case, and the jury agreed.”

The slaying occurred about 9:30 p.m. April 12 inside Bermudez Leon’s Riverdale home in the 6600 block of 60th Avenue. Vargas, his wife and their two young children shared the home with Bermudez Leon.

When police arrived, they found Bermudez Leon dead in a ground-floor bedroom. She had been stabbed about 40 times, authorities said.

Vargas had a broken nose, which was bleeding heavily. He was taken to Prince George’s Hospital Center for treatment.

Vargas told police that three black men had broken into the home, demanded money and attacked Bermudez Leon and him. Two of the men, armed with knives, took Bermudez Leon into the bedroom, where they stabbed her, Vargas claimed.

Vargas told police the third intruder held him at bay with a gun and punched him.

Nonetheless, Vargas said, he broke away, raced into the bedroom and tried to wrest his mother-in-law from the attackers. Vargas said he slipped on a pool of blood while the intruders got away.

County homicide detectives were immediately suspicious of Vargas’s account. The crime scene did not support his story, and there were no bloody footprints from the bedroom to any escape routes. For that matter, there were no escape routes. All of the windows were shut and undisturbed, and the front and back doors had been locked.

A witness account created more suspicion. A family friend who arrived shortly after the killing told police he knocked on the front door and got no response but heard moaning.

The friend said he kicked the door open and saw Vargas repeatedly slamming his face into the floor.

Three days after the killing, Vargas was questioned by county homicide Detective Kelly Rogers. Vargas had been charged in the slaying but was sticking to his story. The interrogation was videotaped, and more than an hour of it was played for the jury.

After telling Vargas that he could ask for an attorney, and establishing that Vargas understood and spoke English, Rogers calmly recited how the physical evidence did not support his story.

“Sometimes good people get angry and do bad things and get stuck in a story,” Rogers said. Vargas insisted he was telling the truth. When Rogers left the room a couple of times, Vargas placed his head on a table and wept and moaned, “My God,” in Spanish.

Rogers later drove Vargas to the county jail. There, Vargas admitted that the intruder story was untrue and said he was sorry for what he had done, Rogers testified.

Vargas testified that he made up the story because he was confused and afraid. He said Bermudez Leon was scolding him for staying out late and for being late on the rent. Vargas claimed that Bermudez Leon attacked him with two knives, which fell to the ground. He said he then picked up a knife and stabbed her in self-defense.

Vargas is scheduled to be sentenced May 25.