Screams from a homeless man being attacked as he slept led officers to capture the man responsible for a string of assaults that have terrorized San Diego's transient population, authorities say.

The arrest of Jon David Guerrero on Friday came five days after police released another man they had suspected in the attacks that left three homeless men dead and two critically injured, including the most recent victim. Two of them were set on fire.

Police told reporters that they have no doubt they nabbed the right man.

Guerrero was arrested in the pre-dawn hours soon after a fifth transient was attacked under a freeway bridge. Two officers heard the 55-year-old man's screams and found him with severe trauma to his upper body — like the other four victims, Capt. David Nisleit said.

Police found Guerrero riding a bicycle nearby and uncovered physical evidence at the scene and at his downtown San Diego residence linking him to all the crimes, Nisleit said.

He would not give details about the evidence or the victims' injuries because investigators are still talking to witnesses and want to ensure the credibility of their stories.

"We have the right person in jail," Nisleit said.

A phone number could not be found for Guerrero, who grew up in the wealthy community of Coronado, across the San Diego Bay, known for its mansions and picturesque beaches. Police have not determined a motive and didn't say if Guerrero had a lawyer who could speak on his behalf.

He faces three counts of murder, two counts of attempted murder and two counts of arson in the attacks that Police Chief Shelley Zimmerman called the worst she has seen in her 34 years in law enforcement.

"I firmly believe Guerrero is the suspect responsible for these vicious crimes," she said. "I say that with complete confidence after receiving a thorough briefing from our homicide unit and fully understanding the amount of physical evidence they have collected today and throughout this entire investigation."

In all five attacks, the men suffered severe trauma to their upper body and most had been sleeping alone. Advocacy groups have urged homeless people to sleep closer together in well-lit areas.

Friday's arrest comes after another man was taken into custody July 7 and then released from jail Monday without being charged. Police said there wasn't enough evidence to prosecute him and released a new sketch of the suspected serial killer Thursday.

Guerrero resembles the suspect whose image was caught on a convenience store surveillance video after the first killing July 3. He was wearing a hat Friday similar to the one worn by the man in the video.

The violence began July 3, when police found the badly burned remains of Angelo De Nardo between Interstate 5 and some train tracks. The 53-year-old died before his body was set on fire.

The next day, officers responding to a 911 call found Manuel Mason, 61, who suffered critical injuries to his upper torso. A few hours later, police discovered the body of Shawn Longley, 41, who bled from the upper torso and died.

Dionicio Derek Vahidy, 23, died Sunday at a hospital, four days after he was set on fire downtown. A witness pulled away a burning cloth that the attacker put on him before fleeing.