Complex sentence: Cumpănaş was reportedly close to Polly Hamilton, who was Dillinger's lover, and, once aware of Dillinger's real identity, she considered turning him in as a way of obtaining permanent US residence.
Split into simpler sentences: Cumpănaş was reportedly close to Polly Hamilton, who was Dillinger's lover. Once she became aware of Dillinger's real identity, she considered turning him in as a way of obtaining permanent US residence.