MIAMI -

Two relatives of a missing University of Florida student are having difficulty getting visas to leave Colombia and join the family in the United States.

Sen. Marco Rubio's office says two of 18-year-old Christian Aguilar's aunts have been trying to secure humanitarian travel visas but were denied. His office has been trying to assist them.

Aguilar was last seen in a Gainesville Best Buy store with his friend, Pedro Bravo, who has been charged with first-degree murder. Aguilar's body has still not been found.

The visas were denied on grounds that the women failed to present strong enough ties to Colombia. Both have pending green card applications.