An Illinois woman allegedly used fake ultrasound pictures as part of an elaborate plan to scam cash from men she met through online dating sites, police have said.

Julie Cahlaway is accused of targeting a recently divorced Nebraska man online after moving to Omaha. In total she swindled several men out of $375,000, said authorities.

The 38-year-old forged an ultrasound to convince the Nebraska victim and his mother she was pregnant and needed money to pay legal and medical bills.

Documents submitted to the court said Cahlaway "targeted a lonely and recently divorced male and solicited funds of sympathy for her alleged legal and medical problems."

The papers added that "Cahlaway presented both (man) and (man's mother) with ultrasound/sonograms of a fetus in support of her position."

In total this particular victim handed over $279,000 to Cahlaway.

This also includes $75,000 she took from him as an investment in an oil venture. The court papers state: "Cahlaway made no such purchase and instead purchased a BMW for herself."

Police say Cahlaway spent the money she made from men "on personal shopping", high-end fashion and supporting her side business, which is brokering tropical fish.

Cahlaway is currently on probation from a previous fraud conviction in Minnesota, added police.

She handed herself in to Nebraska police this week, and was arrested and charged with two counts of felony theft by deception. She is being held in Omaha's Douglas County Jail.