JOLIET, Ill. — The murder trial of former suburban Chicago police sergeant Drew Peterson began Tuesday with dueling explanations of his third wife’s death, clashes over evidence and a teary witness’ description of finding her friend’s body.

Prosecutors gave jurors an account that could have come from a 1940s pulp novel, in which a man does whatever he must — including murder — to keep his ex-wife’s hands off his money.

On the other side, Peterson’s attorneys argued the former officer was a victim of something newer: a 24-hour news cycle and cable TV’s talking heads, which together created a media frenzy that did not subside until prosecutors had charged an innocent man.

Peterson, 58, is charged with first-degree murder in the 2004 death of his third wife, 40-year-old Kathleen Savio. He is suspected but not charged in the 2007 disappearance of his fourth wife, Stacy Peterson. He has denied wrongdoing in both cases.

The real-life drama inspired a TV movie and attracted national attention, as many speculated whether Peterson used his law-enforcement expertise to get away with Savio’s murder and make 23-year-old Stacy Peterson vanish.

The prosecution’s witness was Mary Pontarelli, a neighbor who discovered Savio’s body in a dry bathtub, her hair soaked with blood.

“I saw Kathleen in the tub, ran out, threw myself on the ground and started screaming,” she said, her voice cracking.

Pontarelli testified that Peterson then ran up the stairs, took Savio’s pulse and declared somberly, “She is dead.”