San Antonio police say they have arrested a man in connection with the fatal shooting of Detective Ben Marconi.

Otis Tyrone McKane, 31, was taken into custody late Monday afternoon.

San Antonio SWAT team members pulled McKane over on Interstate 10 at about 3:45 p.m., according to Police Chief William McManus. A woman and a baby were in the car with McKane at the time of his arrest. No one was injured.

McKane is a San Antonio resident.

Further details have not been released.

The 50-year-old Marconi was writing out a traffic ticket to a motorist when he was shot to death in his squad car late Sunday morning.

A $25,000 reward is being offered for information on who targeted and fatally shot a San Antonio police officer during a traffic stop Sunday.

McManus said Marconi was not far from police headquarters when he stopped to write a traffic ticket. While sitting in his vehicle, "a person pulled up behind the patrol car in a black vehicle, got out, walked up to the passenger window, fired one round in the vehicle, shooting the officer in the head, reached in and fired a second round, shooting him [the officer] a second time."

"It's everyone's worst nightmare," said McManus.

McManus said he doesn't believe the shooter has any relationship to the original motorist who was pulled over and no motive has been identified.

Sunday's fatal shooting in San Antonio came less than five months after a gunman killed five police officers in Dallas who were working a protest about the fatal police shootings of black men in Minnesota and Louisiana. It was the deadliest day for American law enforcement since Sept. 11, 2001.

"It's always difficult, especially in this this day and age, where police are being targeted across the country," McManus said.

On Sunday afternoon, Texas Gov. Greg Abbott issued the following statement:

"Cecilia and I extend our deepest condolences to the victim's family and harshly condemn this horrific act of violence. We ask that all Texans join us in praying for the officer's loved ones as they deal with the aftermath of this unimaginable tragedy. Attacks against law enforcement officers will not be tolerated in Texas and must be met with swift justice, which is why I look forward to signing my Police Protection Act into law - making targeted attacks against law enforcement a hate crime. "

"Cecilia and I extend our deepest condolences to the victim's family and harshly condemn this horrific act of violence. We ask that all Texans join us in praying for the officer's loved ones as they deal with the aftermath of this unimaginable tragedy. Attacks against law enforcement officers will not be tolerated in Texas and must be met with swift justice, which is why I look forward to signing my Police Protection Act into law - making targeted attacks against law enforcement a hate crime."

Lt. Gov. Dan Patrick also issued a statement:

"We received the sad news today that another Texas police officer has been killed in the line of duty. It appears the officer may have been murdered simply because he was an officer. Jan and I ask you to join us in keeping his family in our prayers.

"More law enforcement officers have been lost in Texas than in any other state. We cannot tolerate our police officers becoming targets on our streets when they are doing their job, which is why protecting law enforcement must remain a top priority for Texas."

NBC 5's Holley Ford contributed to this report.