HILO, Hawai'i — Big Island police hope the mugging of a 61-year-old Washington state woman in downtown Hilo this week will qualify for federal prosecution.

Because suspect Brandon Tisalona, 24, of Kea'au, allegedly assaulted a visitor, and in a separate incident confronted a couple from California, authorities said the case could be pursued as a violation of the Hobbs Act if it can be proven he targeted tourists in crimes that interfered with interstate commerce.

If convicted of robbery under the federal law instead of being prosecuted under state law, Tisalona could face a tougher sentence of up to 20 years in a federal prison, with no chance for parole, said Ron Johnson, major crimes chief for the U.S. attorney's office in Honolulu.

But prosecutors would have to demonstrate the offenses actually stymied interstate commerce, which can be difficult. The U.S. attorney's office declined to accept previous Big Island cases in which tourists were victimized, because the circumstances did not meet the federal requirements.

Hawai'i County Police Department Lt. Randall Medeiros said police plan to consult with federal prosecutors in Tisalona's case.

"We have certain segments of the population that take advantage, such as in this instance where we have a 61-year-old woman (who was assaulted)," Medeiros said. "That's unacceptable."

He said police submitted for review at least two other recent tourist robberies to the U.S. attorney's office, including last year's robbery at Rainbow Falls in which an Arizona couple was attacked by several youths, and the robbery at gunpoint of two teenage cruise ship passengers at Wailoa State Park, also last year.

Tisalona was charged Wednesday with second-degree robbery and two counts of harassment after he allegedly assaulted the Washington woman around noon Monday, demanding money from her. The victim suffered minor injuries but did not need medical attention, police said.

Officers arrested Tisalona after a brief foot chase. During their investigation, it was learned that a California couple also reported being confronted by Tisalona, who allegedly shoved the woman and challenged the man to a fight. A Big Island man also told police Tisalona allegedly challenged him to a fight.

Federal officials said they can't prosecute all tourist robberies under the Hobbs Act because the impact on commerce can't always be proven, and it would have to be proven that the culprit specifically targeted visitors.

The law was invoked in a Honolulu case in which an organized gang selected Japanese tourists for drive-by purse snatchings in 1996 and 1997. The victims were selected because they characteristically carried large amounts of cash and would be quickly leaving the state. One of the robbers was sentenced to 60 years in a federal prison and another to 51 years.

Larry Butrick of the U.S. attorney's office said the effect on interstate commerce was clear in that case because the Japanese Consulate cautioned travelers as a result of the crimes. The robberies also received a great deal of publicity, possibly discouraging travel to Hawai'i.

"The critical link is the impact on interstate or foreign commerce," Butrick said. "If the criteria is there, we will certainly prosecute it and we always leave that open. And we always review these cases when there's a request made by any law enforcement agency."

Big Island police often work with federal prosecutors on drug trafficking and firearms cases.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.