LONDON — Capping a chronicle of illicit sex, bad loans and serial mendacity, a British Army sergeant was convicted on Thursday of trying to murder his wife by tampering with her parachute before a sky-dive as a prelude to life with another woman.

Sgt. Emile Cilliers, 38, had pleaded not guilty to two charges of attempted murder, after a jury found that he tried to kill his wife, Victoria, by first causing a gas leak at the couple’s home and then using his experience as a parachute packer to meddle with his wife’s equipment to ensure that it would not open.

He offered to pay for the jump in April 2015, purportedly as a treat following the birth of their second child, the prosecution said. He will be sentenced later.

The imagery conjured by testimony at the trial riveted followers of the case, in which Victoria Cilliers, a 41-year-old physiotherapist, leapt from an airplane 4,000 feet above the ground unaware that neither her main parachute nor the reserve could open.