My 19 y/o son, Joshua, was found dead in Amsler Park/McGregor, Texas on February 16, 2006. McGregor police did not investigate, telling me, "We don't begin an investigation until something suspicious is found." I told the former Interim Chief that the whole thing is suspicious, because my son would not kill himself.
About two weeks later, I contacted former Det. Martin. He told me, "As of today, the investigation is over." I asked, "What investigation, Molina told me there wasn't one?" He told me he had spoken to my son, Michael, Josh's girlfriend Kayla, and Mr. Holt, a routine jogger in Amsler Park. I knew he hadn't, but to be certain, I told him I would call him right back. I asked Michael and Kayla. Kayla told me that no officer had talked to her. I called Mr. Holt, and he also told me that no officer had come to him, adding that he did return to the 'crime scene', asking why he wasn't stopped as he ran from the scene. He was told, 'because we knew who you were, Mr. Holt.' Michael, who had rec'd a call from Mr. Holt's son, Justin, telling him that someone was hanging in the park, was sent to the park (One block away) to see what was going on, and I asked him to come right back. He didn't. He told me he vaguely remembered Martin speaking to him, but was unable to recall the conversation, as he went into shock when he saw his brother!
I called Martin, telling him he hadn't talked to anyone but Michael. He said he found out all he needed to know from him.
Homepage of AmericaIsWatching.org - Fighting Injustice in America (http://www.americaiswatching.org) (Joshua Robinson) attached documents, including a crime scene photo and statement that a patrol officer was the last person to see Josh alive in Amsler Park @ 1AM! He died between 1:15 and 2:15AM, according to the rigor/livor mortis.
Do I have a civil/criminal case? How do I prove that the police murdered my son?

You need to hire a private investigator to determine if you have a case. However, if this is a 3 yr old case, I doubt if anything can be done now.