Ex-boyfriend, 17, is arrested for shooting Texas 15-year-old TWENTY TWO times in the back while she walked her dog after she confronted him about his infidelity

  An ex-boyfriend has been arrested and charged with murder in the killing of a 15-year-old girl who was shot 22 times as she walked her dog...

 An ex-boyfriend has been arrested and charged with murder in the killing of a 15-year-old girl who was shot 22 times as she walked her dog near her home in southwest Houston last week, police said Tuesday.

Diamond Alvarez was killed on January 11 a couple of blocks from her home near a field that was used as a neighborhood park. 

In their investigation, police learned that Alvarez was meeting her ex-boyfriend, 17-year-old Frank Deleon Jr., around 9.30 pm last Tuesday, to confront him for dating her while he was in a long-term relationship with another girl.

That's when Deleon shot her 22 times in the back, according to the Houston Police Department.  

Frank Deleon Jr. of Houston, 17 (pictured) was charged with the murder of his ex-girlfriend Diamond Alvarez, who was shot 22 times in the back on January 11

The Houston Police Department said that Diamond Alvarez, 15 (pictured) had learned that Deleon was dating another girl while they were still in a relationship, and went to confront him the night that he allegedly shot her dead

Houston police secures crime scene where Diamond Alvarez was murdered last Tuesday

Alvarez´s mother, Anna Machado, said Tuesday that Deleon was her daughter´s ex-boyfriend and he had texted to ask her to meet him at the field shortly before she was killed.

Alvarez and Deleon had dated for under a year, and the 15-year-old's mother said that her daughter was 'always crying about him' and they were 'off and on'

The two had been going out for less than a year and Machado said she never saw any red flags to warn her that her daughter was in danger, but that 'they were off and on.'

'My daughter was always crying about him,' Machado said.  

Deleon lived less than a half-mile from Alvarez, according to the Houston Chronicle. He was arrested and charged with murder on Monday night. 

In court documents asking for a $250,000 bond, prosecutors said Deleon was 'attempting to pack his bags to flee the jurisdiction' and had a suitcase and clothes on his bed when he was apprehended by police. 

Court records do not list an attorney who can speak on Deleon's behalf. 

Machado said hopes a judge orders Deleon be held without bond.

'He doesn´t even deserve a high bond. He executed my daughter,' she said.

 On the night of the teen's death, Alvarez's family told Houston NBC affiliate KPCR that they became concerned when they heard multiple gunshots while the teen was out walking their dog, Peanut. 

A makeshift memorial sits near the side of a street in Houston, next to a large grassy area where Diamond Alvarez was fatally shot

Alvarez's mother, Anna Machado (pictured) tried to revive her dying daughter with CPR after she and her family found her riddled with gunshot wounds. She said that she hopes a judge won't release Deleon on bail: 'He doesn´t even deserve a high bond. He executed my daughter,'

 Moments later they heard scratching at the door and found the animal, with his leash and harness covered in blood, had run back to the home. 

'When they saw Peanut by himself, they knew something was wrong,' said Ashley Machado, the teen girl's older sister. 

They quickly ran to find her.

Alvarez's mother Anna Machado said her youngest son found Alvarez in a field, by the side of a road on 15400 Park Manor near Markwood Lane.

 She was still alive, and her mother desperately tried CPR, but she died at the scene.

'My son found her. I tried CPR, and I couldn't bring her back. I tried so hard to keep her alive. I couldn't,' Anna told local Fox affiliate KRIV-TV. 

Paramedics declared her dead at the scene. 

Alvarez's stepfather, Tito Moczygenba, said that whoever 'shot this girl in the back 22 times [is a] coward.' 

Alvarez was described as a straight-A student, who played volleyball and basketball, and was looking forward to a career as a beautician

Alvarez's step-father, Tito Moczygenba, said that whoever 'shot this girl in the back 22 times [is a] coward'

The Houston Police Department said neighborhood residents claimed to have heard multiple shots and that a dark-colored car reportedly sped off from the site of the attack, traveling north on Markwood Lane.

She was described as a straight-A student, who played volleyball and basketball, and was looking forward to a career in cosmetology. 

A makeshift memorial with candles, stuffed animals and balloons has been set up at the spot where Alvarez was found.  

Machado said she is relieved an arrest has been made. 

'I went up over there (to the memorial) again, crying and said: "Baby you have justice. It´s not done yet. It´s not over yet. But at least we know a name,"' she said. 

 Alvarez's funeral service  is set for 11 a.m. Friday in Houston.  

Diamond Alvarez (fourth from left to right) with her family members on New Year's Eve