Capitol police say it turns out the suspicious packages investigated in the U.S. Senate on Wednesday weren’t hazardous.

But spokeswoman Makema Turner said a man was still being questioned late in the day after being stopped in connection with the packages.

The packages raised concern after the FBI said that letters mailed to President Barack Obama and Sen. Roger Wicker of Mississippi tested positive for poisonous ricin. Those letters were sent for more extensive testing, because field tests often yield false positives for ricin.

Authorities closed some parts of Senate office buildings while they investigated the packages. The Capitol was already on edge because of Monday’s Boston Marathon bombings.