A "significant DNA link" convinced prosecutors Friday to drop charges against a man accused of killing his mother and older brother in October and instead has connected suspected serial killer Itzcoatl Ocampo to the crimes.

At a hastily called evening news conference, Orange County Dist. Atty. Tony Rackauckas said Eder Herrera, 24, would be released from Orange County Jail and that two additional murder charges would be filed against Ocampo on Monday.

However, he cautioned, "We're not saying that Mr. Herrera is not guilty."

Ocampo, 23, is already accused of fatally stabbing four homeless men in northern Orange County, what authorities say was part of a weeks-long stabbing rampage that began days before Christmas and ended with his arrest Jan. 13. One victim was stabbed more than 60 times.

Rackauckas noted similarities between the deaths of the homeless men and the Oct. 25 slayings of Raquel Estrada, 53, and her older son, Juan Herrera, 34, at their Yorba Linda home. Estrada was stabbed more than 30 times while Herrera had more than 60 wounds.

He also said DNA found on items taken from Ocampo's Yorba Linda home matched a profile from the double homicide.

"This case has now expanded from murdering random vulnerable strangers to murdering people he knew," Rackauckas said.

Eder Herrera and Ocampo were classmates, Rackauckas said, graduating together in 2006 from Esperanza High School in Anaheim.

In addition, Ocampo lived about a mile from the Herrera home.

According to a friend who has knowledge of the case, Ocampo visited the Herrera home days before the killings to spend time with his buddies.

The friend, who requested anonymity because the investigation is ongoing, said Ocampo's perplexing mental state was noted.

Rackauckas said Estrada's body was found in the kitchen. Prosecutors believe that Juan Herrera tried to escape out the front door, where police found a large amount of pooled blood.

His body was found in the hallway of the home. Investigators did not find evidence of forced entry.

At 11:30 p.m., Brea police responded to a 911 call from an unidentified person who said they heard strange noises coming from the home.

Eder Herrera, who owned a small business with his older brother, was arrested the next morning as he drove away from a friend's house. Last month, he pleaded not guilty to the crimes.

Rackauckas said Friday that there had been "significant evidence" resulting in charges against Herrera.

On that night, Herrera was driving randomly in the area with a friend. "His behavior was in general suspicious," Rackauckas said.

In addition, a witness saw a person he believed to be Eder Herrera dragging something from the front door threshold back inside.

Also, near the spot where the anonymous 911 call was placed, surveillance video showed a person who looked like Herrera walking, wearing shoes with a distinctive side pattern that looked like the shoes he was wearing when he was arrested.

Rackauckas said Herrera also made no effort to check on his mother and brother, despite driving by the crime scene with his friend and seeing police cars in front of the home.

That friend urged Herrera to call his family members on their cellphones. They didn't answer.

A task force continued to investigate the crimes, but Rackauckas said that as of Friday afternoon, that there was "no longer sufficient evidence to hold Mr. Herrera in custody."

At 4:45 p.m., charges were dismissed against Herrera, who was facing 52 years to life in prison, but Rackauckas said that the "door is open" regarding new charges.

Randall Longwith, Ocampo's attorney, said he had not spoken with his client regarding the latest charges. "To me, it doesn't fit," he said.

Ocampo will be arraigned Monday morning.

The homeless murders shot fear through the transient community and were the first serial killings to shock the region in more than two decades.

After Ocampo's arrest, family and friends recalled how he apparently had sympathy for the poor and, despite being unemployed and broke, donated to the homeless.

They also said after he was discharged from the Marines in June 2010, he seemed different.

nicole.santacruz@latimes.com

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