Wallets have been the main targets of the thefts. Police believe that the robber or robbers is interested primarily in cash, as none of the credit cards in the wallets have been used.
Nonetheless, police caution that from the outside a thief cannot tell what a wallet contains.
"Even a wallet with no cash but one credit card is valuable," McNamara said.
No suspicious people have been reported in the area, McNamara said.
HUPD and the library officials said they will work together to ensure students' safety.
If the thefts continue, they might consider taking additional safety measures.
"HUPD told the libraries they'd have a presence, to be proactive, to make sure nothing became an epidemic," Brainard said. "We always want to make sure we're doing the best for our users. Whatever it takes."