HOUSTON -- Police spent hours on Monday gathering evidence in hopes of catching a killer who murdered a grandmother in broad daylight. 

In the end, the man they were looking for came to them.

James Thompson turned himself in Monday night.  Police charged the 42-year-old with murder.

"He killed my sister. He killed her in cold blood. He didn't have any mercy for her. She was a beautiful person that did not deserve this at all," said Eronica Teapo, victim’s sister.

Thompson allegedly shot Giselle Teapo as she headed to work Monday morning. According to reports, he shot her multiple times, hitting her in the head and stomach.

The two had been in relationship, but family members said that Teapo had recently left him.

Family members said that Giselle Teapo did what she could to distance herself from Thompson. After they broke up, she moved out the house they shared, and even got a restraining order. But in the end it simply wasn't enough.

"She informed me that he called her.  She had 232 missed calls from him on her cell phone. He was a sick individual," said Eronica Teapo.

Experts report that the most dangerous time for a woman in violent relationship is when she tries to leave.

"If the batterer thinks that he has lost control or lost power over someone, that's when he escalates his behavior," said Kelly Young, Women’s Resource Center.

In this case, authorities said the controlling behavior turned violent and led Thompson to murder.

"I'm elated that he's caught. I thank God that justice will be served because I believe in my justice system," said Eronica Teapo.

The family has set up a Giselle Teapo Memorial Fund through Bank of America. Donations to help the family with funeral expenses can be made at any Bank of America branch.