The gunmen then scrambled over the roofs of the houses and tried to escape, but they were tracked down by the security forces and the shooting resumed in the streets.

The young woman is pregnant and news reports said Garza Pescador was the child's father.

'I saw quite a lot of her until she was 16. Her mother died and I sought her out to give her my support, so she could study. But she left school, she got married and later I didn't see her again,' Medina Trevino said.

'You never expect this kind of thing from your children, and I believe that this child lacked support, someone to guide her and here are the consequences,' the police chief said.

Medina Trevino is also the father of former Monterrey police chief Amador Medina Flores, who is currently under investigation by federal authorities for his suspected links to drug traffickers.

Another of his children, Alberto Medina Flores, was the police chief of Santa Catarina, another city in the area, but he resigned in August 2007, apparently amid threats from criminals.