SANFORD, Fla. -

Attorneys for George Zimmerman, the neighborhood watchman charged with shooting and killing Trayvon Martin, have released reports from the shooting's lead investigator in the case against Zimmerman.

The evidence includes reports from the lead investigator from the Sanford Police Department in the shooting, Chris Serino.

[READ: Document 1 | Document 2]

The documents released on Tuesday include five versions of lead Sanford Police investigator Chris Serino’s  “main supplemental report” – all of them dated March 13, 2012.

In the first two versions, which were saved at 9:40 a.m. and 1:31 p.m., Serino makes a case for a  second-degree murder charge against Zimmerman.

In the later three versions -- saved at 1:54 p.m., 2:06 p.m. and 2:23 p.m. -- Serino’s narratives conclude with requests for a manslaughter charge.

The manslaughter charge wound up on the document submitted later that day to the state attorney’s office, as it was asked by Sanford Police to decide what if any charge Zimmerman should face.

Also included in the newly released discovery are audiotape recordings of an interview with Witness 8, Martin’s girlfriend. She tells Martin family attorney Benjamin Crump she was on the phone with Martin often on the day he was shot, including just before he died.

A previously released copy of the interview was difficult to understand and, while this one is of better quality, it still is difficult to decipher.

The last document released today is a March 15, 2012 email from Sanford Police Capt. Robert O’Connor to 14 members of the Martin homicide investigation team and then-chief Bill Lee.

He thanks them all, acknowledges the “stress” they are under from public outrage over their decision not to arrest Zimmerman. Then, he adds, “In spite of the beating we are taking in the court of public opinion, it is important to reach back and realize that we are all professionals and we do what we do for the right reason, not a popular outcome.”

He admits “second guessing my decisions,” but concluded, “After much reflection, I no longer feel uneasy about our direction.”

One week later, after getting a call from Florida Attorney General Pam Bondy, state attorney Norm Wolfinger removed himself from the case and Gov. Rick Scott appointed a special prosecutor, who, on April 11, charged Zimmerman with second-degree murder.

Zimmerman is pleading not guilty to second-degree murder, claiming self-defense. His trial is set for the middle of 2013.