BOSTON – Photographing women’s private parts in public by aiming a camera up their skirts violates no Massachusetts law, the state’s Supreme Judicial Court ruled Wednesday.

The ruling dismissed voyeurism charges against a man transit police arrested in 2010 after receiving complaints he used his cell phone to capture “upskirt” images of female subway passengers. According to the justices, Massachusetts’ “Peeping Tom” law prohibits surreptitious filming of nude or partially nude individuals in bathrooms and other places where they have a reasonable expectation of privacy, but the law does not prohibit photographing those who are fully dressed in public.

“A female passenger on a MBTA trolley who is wearing a skirt, dress or the like covering these parts of her body is not a person who is ‘partially nude,’ no matter what is or is not underneath the skirt by way of underwear or other clothing,” Justice Margot Botsford wrote in the court’s decision. Current state law “does not apply to photographing … persons who are fully clothed and, in particular, does not reach the type of upskirting that the defendant is charged with attempting to accomplish on the [Massachusetts Bay Transportation Authority].”

Even though women should have “a reasonable expectation of privacy in not having a stranger take photographs up her skirt,” law enforcement officers and the courts are not allowed to read into a statute extra conditions the law does not specifically address, the decision also noted.

State legislators moved quickly to close the legal loophole. Lawmakers led by House Speaker Robert DeLeo [D-Winthrop] scrambled on Thursday, attempting to craft a bill that would prohibit upskirting without running afoul of constitutional guarantees. DeLeo said legislators hoped to have a bill ready for Gov. Deval Patrick’s signature as early as Thursday evening.

“We want to make sure that we get the language right,” DeLeo said. The idea of legalized upskirting is “something which appalls us greatly. We’re outraged by what has occurred, and we want to make sure that these types of actions are dealt with in our court system and dealt with swiftly.”

MBTA authorities have investigated 13 upskirting allegations over the past three years. It is unclear how many of the investigations resulted in charges or how the Supreme Judicial Court’s Wednesday ruling might affect the cases that remain open.