Trey Songz Was The Reason Earl Hayes Killed His Girlfriend & Himself?

Earl Hayes -- the man who cops say shot his famous wife to death Monday and then killed himself -- was haunted by her infidelity ... in particular what he said was a fling she had with singer Trey Songz.

Stephanie Moseley -- the star of VH1's "Hit the Floor" -- was gunned down in their L.A. apartment as neighbors heard her screaming. Shots rang out, the SWAT team came, busted through the door and discovered the 2 bodies.

Sources connected with Hayes tells TMZ ... around 2 years ago he separated from Stephanie because of what he says was her affair with Songz. They got back together but, as one friend put it, "He was crushed and never got over it." He frequently brought up Songz.

Hayes accused Moseley of having multiple affairs with various other entertainers. She was a backup dancer who worked with numerous famous singers, including Chris Brown and Usher, but Hayes never mentioned them as a source of conflict.

Hayes and Moseley married in 2008 and his friends say he loved her and tried rationalizing staying together.

Floyd Mayweather was on FaceTime with Hayes when he flew into a rage over Moseley's alleged infidelity and the boxer was witness to the murder/suicide.

In other news …. They are trying to say Floyd Mayweather put the battery in that ni**a back …..

Floyd Mayweather whipped his friend Earl Hayes into a frenzy over his wife's infidelity ... to the point Hayes gunned her down ... and now the LAPD wants to sit the boxer down for questioning ... multiple sources tell TMZ.

Floyd was on FaceTime with his rapper friend Monday morning when the shots were fired. Now we're told, Floyd was telling Hayes he should leave his wife, Stephanie Moseley -- a well-known backup dancer and star of VH1's "Hit the Floor" -- because she was bad for his career.

Hayes was distraught over what he believed was repeated infidelity, including a fling he said Stephanie had with Trey Songz.

One Mayweather source says Floyd challenged Hayes, saying he was weak for not leaving her.

At that point, as Floyd was on FaceTime, Hayes went off and said he was going to gun down Stephanie. We're told Floyd didn't even know Stephanie was in the apartment, but when he realized it the boxer begged Hayes not to go through with it.

Law enforcement sources say Hayes went into the bathroom and fired 10 to 12 shots as Stephanie was taking a bath. We're told she was hit multiple times.

Neighbors who heard the shots called the LAPD and cops rushed to the scene, but when they got to the door they heard another shot and retreated. That shot was Hayes taking his own life.

The SWAT team showed up and broke down the door. Cops found Stephanie's body in the bathtub and Hayes was in the bedroom.

The LAPD wants to interview Floyd ... presumably because he was a witness to the murder-suicide.

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