Two other police officers were also shot Sunday night, but it wasn't clear whether the incidents were targeted attacks.
Authorities say a San Antonio detective writing out a traffic ticket to a motorist was shot to death in his squad auto late Sunday morning outside police headquarters by another driver who pulled up from behind.
The alleged suspect 31-year-old Otis McKane was arrested Monday afternoon, SAPD officials said. While being walked out of the police department, McKane said he had gone through several custody battles and "lashed out at someone who didn't deserve it". He said he wished to apologize to the family of the slain officer.
McManus said Marconi had pulled over a vehicle and while he was inside his squad auto writing a ticket, a auto pulled up behind him. The sergeant was released from the hospital Monday.
The shooting was one of several weekend attacks that authorities say targeted law enforcement in multiple states. Of the 60 killed, 20 were purposely targeted by their assailant compared to eight previous year, the group said. Officers also were shot and wounded Sunday night during traffic stops in Sanibel, Florida, and Gladstone, Missouri. All the shootings come less than five months after a black military veteran killed five white officers at a protest in Dallas - the deadliest day for American law enforcement since September 11, 2001.
Race was a factor in Dallas, but police have not said if race played a part in any of the attacks on Sunday.
Capt. Doug Shoemaker with Jefferson City Police Department says, "When an officer conducts a traffic stop, generally he or she doesn't have any idea who they are walking up on".
The National Law Enforcement Fund, an organization that tracks police officer deaths, said that the total number of fatalities this year has increased by 16 percent. A woman and a 2-year-old child were with him in the vehicle, police said. McManus said they have not yet been able to establish a motive in the shooting.
A police officer has been fatally shot in San Antonio, Texas, and another in St. Louis was shot in the face but is expected to survive, in what authorities are calling the latest in a series of target attacks on law enforcement.
The suspect asked a desk clerk a question but left before receiving an answer, said Mr McManus, who declined to say what the man asked.
"I don't know why he was in headquarters. Also, there were leads from outside the area, so we had Federal Bureau of Investigation around the country working leads and then we had assets back in Quantico working on video enhancements and some other things to try and identify the subject", said Combs. "I am still convinced that he was targeting blue - targeting a San Antonio Police Department officer, no matter who it was".
The man walked up to the patrol vehicle driver's side window and shot the officer in the head, McManus said. Police reported early Monday that the suspect was later killed in a shootout with police. "That's why he aggressively attacked a police officer".
McManus likened the shooting to the fatal ambushes of police officers in Dallas, Texas, and Baton Rouge, Louisiana, earlier this year. Officers are being reminded to practice "situational awareness", to expect the unexpected and to "never take any assignment for granted", he said.
Just before 8 p.m. Sunday, an officer was working a traffic stop when a man drove by and opened fire, according to a police statement.
In fact, he said, white men are responsible for most police slayings, and the majority of people shot and killed by poIice are white.
"It's always hard, especially in this day and age, where police are being targeted across the country", McManus said.
This update has been corrected to show that the suspect was arrested in a vehicle that he was riding in, not a auto that he was driving, and to show that the suspect's last name is "McKane" and not 'McCain'.