Retired Las Vegas metro police department detective sergeant John Samolovitch, who was head of the sexual assault unit at the time, confirmed to DailyMail.com "the copy of the police report is in fact a true copy of the original report.'"
DailyMail.com contacted Stallone's representative for comment, but has not received a response.
After the incident, the teen claims Stallone threatened her - she couldn't tell anyone because both men were married and if she said anything, "they would have to beat her head in", before laughing with De Luca.
The unidentified teen ultimately decided not to pursue charges against either men because she was "humiliated and ashamed", as well as being "scared", according to the police report.
At the time of the incident Stallone, now 71, was 40-years-old. Bodyguard De Luca, who was shot and killed by California police during a traffic stop in 2013, was 27-years-old at the time.
Police were alerted to the incident when a hotel employee called police to report that a friend of the victim said she needed advice on the matter.
When officials tracked down the teen, she relayed details of the alleged assault to them.
She said she was staying at the Las Vegas Hilton hotel with family friends for 10 days, from July 18 to July 28, during the time that Stallone happened to be filming at the hotel for the upcoming movie Over the Top.
The teen said she met actor David Mendenhall, who was playing Stallone's son in the film, at the hotel's arcade and he introduced her and her cousin to Stallone on Wednesday, July 23, 1986.
In the following days, the cast and crew of the movie continued filming at the hotel, and on Friday, the teen said she saw Stallone and got his autograph.
According to the police report, Stallone asked the girl how old she was and after learning she was 16-years-old, he asked her "how she got such a build".
One of the teen's friends had received a kiss on the cheek from Stallone during the conversation, so the teen said she also asked for a peck on the cheek from Stallone.
"He replied that he would give her a kiss at a later date, that she would not forget", according to the police report.
The next day the teen said she returned to the area in the hotel where the crew was filming with a larger picture for Stallone to autograph for her so that she could give it to a friend.
There, she met De Luca, Stallone's bodyguard, who allegedly asked the teen if Stallone made a pass at her, what would she do.
The teen said she responded that she "would probably make a pass back at him".
De Luca then gave her two keys for a room on the 27th floor and told her "to go up to the room as soon as possible," according to the police report.
That night, the teen claims she went up to the 27th floor where she met Stallone and De Luca in the hallway and together, they all went into the hotel suite.
From there, the teen said she and Stallone went into the bedroom, got undressed and began having brief intercourse, while De Luca stayed in the bathroom.
Stallone asked her if she ever had sex with two men at the same time, according to the report.
She said she responded that she hadn't and then Stallone went into the bathroom and brought De Luca into the bedroom.
The minor claims De Luca forced her to perform oral sex on him for a few minutes and then intercourse.
Then Stallone allegedly "came over to her and pushed her head down" and made her perform oral sex.
The teen told police that after she got dressed, "Stallone made the comment that they were both married men and that she could not tell anybody about the incident and if she did, that they would have to beat her head in".
Stallone and De Luca both "laughed after he made the comment", according to the report.
Police noted that "during the interview [the teen] became emotionally upset numerous times, crying and sobbing."
The report continued: She indicated that if the sexual encounter had only been with Stallone, she would not pursue this matter, but due to the fact that Mike, the bodyguard became involved in the sexual incident, she didn't know what she wanted to do."
According to police, when De Luca became involved in the sexual encounter "she became very uncomfortable with the situation. She states she did not want to have any type of sexual contact with the bodyguard, but felt she had no choice in the matter.
"She states there was no actual physical force, but she did feel intimidated."
Police noted in their report that the teen had "difficulty in relating her thoughts" and was "extremely emotional" when telling her story.
When pressed if she wanted to pursue charges against Stallone and De Luca, the girl told police: "I'm humiliated and ashamed, but I don't want to prosecute.
"I'm kind of scared and I'm very ashamed. I don't want anybody else to have that happen to them, but I don't want to prosecute. I cannot talk about this anymore, please leave me alone."
She later signed a no prosecution form and the matter was dropped, although police did confiscate De Luca's concealed weapon permit on July 30, 1986.
The bombshell police report was made a year before Stallone's half-sister Toni-Ann Filiti, threatened him with a lawsuit in 1987, alleging that Stallone raped her and sexually assaulted her for years.
Although court documents show the actor "vigorously denied and continues to deny and dispute all claims of wrongdoing", he agreed to give Filiti a lump sum of US$2 million, as well as US$16,666 a month for the rest of her life.
His half-sister, whose own mother claimed she was a drug addict, died in 2012 after a battle with lung cancer.
Stallone is one of the most recent A-listers in Hollywood to be accused of sexual assault and/or harassment in the wake of damaging claims made against Harvey Weinstein, Kevin Spacey, Louis C.K., Brett Ratner, among several others.
