Nassau and Suffolk police and officials are warning of an uptick in scams targeting Long Islanders, including one using a popular buying and selling app.

In November, Jocelin Elan, of Port Washington, received a call from someone threatening to arrest her. The caller claimed she had serious allegations against her, but Elan didn't fall prey. She says what was most concerning is that the caller reached her cellphone and left two voicemails.

Suffolk County officials call those types of scams the modern-day version of highway robbery.

Officials say a common scam includes someone claiming they're from the IRS or an electric company and asks for immediate payment. Police say that would never happen.

Suffolk officials also remind the public that scams come in many different forms, including most recently a scam that involved the Letgo app. They say five people in the Mastic Beach area met to buy or sell items and were instead robbed.

Police say if something sounds too good to be true or if threats are being made, you're likely being scammed.