PHOENIX -- Saturday marks the two-year anniversary of Daniel Ramirez's murder.

His grandmother, Rosemary, Mead, worries she will never see justice for her grandson.

Daniel Ramirez, 17, was shot at a party on July 4, 2007.

No arrests have been made.

"I do not think their investigation was thorough enough,” Rosemary Mead said. "Anyone I know that's been questioned has said it's a joke.”

• Read: Statement From Sgt. Andy Hill

The first lead detective assigned the Ramirez’s case was Richard Polk. Polk pleaded guilty to attempting to buy child pornography earlier this year.

Mead said detective Heather Polombo replaced Polk. She has been the frequent target of attacks on a Web site critical of Phoenix police.

“That investigation was initiated due to a harrassment complaint by a female Phoenix police officer," said Sgt. Andy Hill. "Harrassment is unacceptable and will be investigated. The investigation led us to find harrassment of a Phoenix Police Department sergeant as well and has expanded into serious criminal offenses because we follow the investigation wherever it takes us.”

Mead said Polombo has not followed up on leads or pressed witnesses at the party for answers.

Mead also said police told her they know who killed her grandson.

“How can the police department and the higher ups look you in the face and say we know who killed your grandson, but we can't do anything about it? We just don't have the evidence,” Mead said about a meeting she had with police.

Mead has launched her own investigation and hired a private detective.

She said she gives information she finds to Phoenix police.

As the two-year anniversary of her grandson’s murder has arrived, Mead said she has little hope police will ever find his killer

“My opinion is justice for Danny will only be done if I can fight till I die,” Mead said.

Daniel Ramirez was shot as he was standing up to give a girl his seat on a patio at The Retreat apartment complex on Rose Garden and 27the Avenue.

Mead said the killer fired eight shots at the patio from the street. Ramirez was hit in the chest and died on the scene.