A defense attorney may have to pay sanctions for a binder containing sensitive prison gang documents that was found in a downtown Honolulu eatery.

Defense attorney Marcus Sierra said at a hearing Thursday that the binder is his and he’s not exactly sure how it ended up out of his possession. He said he’ll take steps to make sure it doesn’t happen again, such as keeping evidence boxes sealed while being transported between court and his office and not leaving them in the courtroom overnight during a trial.

Federal prosecutors requested Thursday’s hearing after learning that the binder ended up in the eatery last month after a trial where a former Halawa Correctional Facility guard was convicted of taking bribes from the "USO Family" prison gang to smuggle drugs to inmates. A Halawa inmate represented by Sierra was found guilty of leading a brutal assault for the gang.

Prosecutors were concerned because, if the binder got into the wrong hands, it could have dangerous consequences.

There was testimony during the trial that gang members routinely use court documents to try to find out who’s snitching. Trial witness lists in the public record contained blacked-out names of the inmates who were testifying.

The judge in the case ordered previously that attorneys for the defendants can show copies of witness material to their clients but can’t provide them with copies.

U.S. District Judge Leslie Kobayashi said Thursday she’ll look at the binder’s contents and consider prosecutors’ legal fees before determining whether there should be sanctions against Sierra.

Prosecutors initially said the binder was found at Alakea Deli, a restaurant that Sierra said he hasn’t patronized in months. He said Thursday that prosecutors have since informed him the binder was actually found at another eatery down the block, where he had stopped for coffee after long trial days.

"It is plausible … that I may have been at fault for leaving it there somehow," he said. He added it wasn’t done intentionally.

Kobayashi agreed it didn’t appear intentional and said how it ended up there is beside the point.

"The point is it contained confidential information that if found by certain elements can result in significant and even serious, maybe even deadly, harm to others," she said.

It doesn’t look like any of the documents ultimately landed in the wrong hands, Assistant U.S. Attorney Jill Otake said. But she said worried relatives of some witnesses have contacted her nonetheless.