WASHINGTON – A loophole that permits software companies to sell cyberstalking apps that operate secretly on cellphones could soon be closed by Congress. The software appeals to some jealous wives or husbands because it can continuously track the whereabouts of a spouse.

The Senate Judiciary Committee approved a bill Thursday that makes it a crime for companies to make and intentionally operate a stalking app. The legislation, sponsored by Sen. Al Franken, D-Minn., also would curb the appeal for such inexpensive and easy-to-use programs by requiring companies to disclose their existence on a target’s phone.

Stalking and wiretapping already are illegal, but there are no provisions in federal law that clearly prohibit businesses from making an app whose primary purpose is to help one person stalk another. Franken’s proposal would extend the criminal and civil liabilities for the improper use of the apps to include the software companies that sell them.

The proposal would update laws passed years before wireless technology revolutionized communications. Telephone companies currently are barred from disclosing to businesses the locations of people who make traditional phone calls. But there’s no such prohibition when communicating over the Internet. If a mobile device sends an email, links to a website or launches an app, the precise location of the phone can be passed to others.

The ambiguity has created a niche for companies like Retina Software, which makes ePhoneTracker and describes it as “stealth phone spy software.” It’s available online for about $50. “Suspect your spouse is cheating?” the company’s website says. “Don’t break the bank by hiring a private investigator.”