laci peterson crime scene

Pregnant Laci Peterson was punched in the stomach and beaten to death by her cheating husband Scott!

That's the chilling scenario sources close to the investigation laid out after Scott's April 18 arrest on charges he murdered his wife and unborn child.

The issue that goes on sale Friday reveals how cops believe Scott killed Laci -- and why -- the secret evidence against him, how cops used Scott's lover to trap him … and much more.

• KILLER MOM SUSAN SMITH NOW PRISON DRUG QUEEN
• MISSING UTAH MOTHER: HUSBAND TEARS DOWN SHRINE
• RETIREES' REVENGE
• WOMAN VP EMBEZZLES STAGGERING $31 MILLION --COPS CHARGE
• MURDERED FOR HIS MILLIONS
• MOM TURNS IN HER OWN SON IN BANK HEISTS
• SPURNED WOMAN MURDERS BEAU'S NEW GIRLFRIEND - & HER HUSBAND -- COPS CHARGE
• MYSTERY OF DISAPPEARING HUSBAND SOLVED!
• CASE OF THE BANK ROBBING SOCCER MOM