SAN ANTONIO — Detectives say a suspect has been arrested in the shooting death of Det. Benjamin Marconi.

Police took 31-year-old Otis Tyrone McKane, a San Antonio resident, into custody Monday afternoon without incident. In his own words, McKane told reporters why he fired upon Marconi.

"Society not letting me see my son, I lashed out at somebody who didn't deserve it," McKane said.

Police say surveillance video shows McKane early Sunday when he went into SAPD headquarters four hours before the shooting.

Authorities believe he was the gunman who walked up to Detective Benjamin Maroni's patrol car and shot him twice at point-blank range.

Chief William McManus says his department feels a great sense of relief, but his officers must stay alert.

"Well the fact that he's been taken into custody - that does not negate the fact that there are people out there who are still targeting police officers, so our officers will always be vigilant and on guard for that," said McManus.

SWAT tailed McKane for several hours before making the arrest. They stopped McKane in a car with a woman and child inside, but they were unharmed. McKane was not in the car used during Sunday’s shooting.

McKane is charged with capital murder. The district attorney says it's too early to say whether his office will seek the death penalty.

RAW VIDEO: Suspect Says 'I'm Sorry'