SAN ANTONIO -- During an exclusive interview with KENS 5, Johnny Joe Avalos said he's been keeping a secret: more murder victims.

But he wanted payment for his confession. KENS 5 does not pay for interviews. Avalos decided to talk about it anyway.

"I'm not going to tell you what happened with the other girls... four other girls," Avalos said. "There's one that they (police) don't know about. And, I'm about to admit it to you."

The 28-year-old does not deny he has killed three women and a teenage girl.  As a matter of fact, when given the names of the victims, he seemed unbothered by the topic. He is suspected of killing 15-year-old Natalie Chavez, 29-year-old Celia Lopez, and 46 year-old Genevieve Ramirez. San Antonio police also consider him a person of interest in the death of Rosemary Perez.

"I'm about to admit to you things that I have never admitted to detectives," he said.

Chavez was found dead under a bridge in the 2400 block of Vera Cruz in December 2014. An arrest document indicated that Avalos' DNA was on her body. The warrant claimed he confessed to having sex with the teen for money. However, his sex for money claim was never publicly proven.

"I can tell you what happened before and I can tell you what happened after," Avalos said. "I knew she was 15. Blah. Blah. Blah."

Lopez's body was found in a vacant lot in the 4400 block of South Presa Street on April 15.  Investigators said her body was decomposing. According to an arrest warrant, the 29-year-old was partially clothed. Police said Avalos confessed the killing to a confidant. He reportedly murdered the woman to steal her money.

Lopez, per the warrant, was not his first female assault or robbery victim. Investigators said Avalos's DNA was found on men's underwear near the woman's remains.

Avalos is also a murder suspect in the beating death of Ramirez. She was found partially dressed and brutally beaten in an alley in the 100 block of Avondale Avenue. That was in April. The 46-year-old died in June. When asked about her death, he replied: "Oh yeah, yeah."

Police have filed paperwork to have Avalos charged with her murder. However, Special Crimes Division Chief Jim Wheat with the  Bexar County District Attorney's Office said they can't move forward with the charge until the case is complete.

Investigators believe Avalos is also connected to the death of Perez. Her body was found wrapped in a sheet in the 2100 block of San Fernando in January. Bexar County investigators have not confirmed Perez's death was a murder. Her cause of death is listed as undetermined.

In exchange for information about the murders, Avalos asked a KENS 5 reporter for $100. After we refused his request, he dropped the price to $50. We said no again. The suspected killer said he wanted to buy a radio and hygiene items. He sought payment 22 times in nine minutes in exchange for the murderous details of his crime, but was always denied.

Avalos is charged with capital murder, sexual assault of a child and murder in the killings of Chavez and Lopez.