PHOENIX – A Mesa man accused of conspiring to kill his grandfather has pleaded not guilty in the case.Devin Almejo, 20, entered his plea Tuesday morning. Almejo is charged with conspiracy to commit first-degree murder.His next court date is Jan. 8.Police said Almejo posted an ad on Craigslist that said he was looking to buy a gun to kill his grandfather.He met with an undercover officer about the ad on Nov. 6. Court documents show that based on Almejo’s inexperience with guns, the undercover officer offered to kill Almejo’s grandfather for him.Almejo offered an iPad, iPod and one year of free haircuts as payment for the murder. They set up a day and time for the killing.The undercover officer said he gave Almejo three opportunities to walk away and told him the murder-for-hire conversation would be forgotten. Each time Almejo said he wanted his grandfather killed.Almejo was arrested after the meeting.Almejo told police that he wanted to kill his grandfather because he had abused him physically, mentally and emotionally.His grandfather denied those allegations, attributing Almejo's comments and actions to "severe mental illness."