Democratic senators from four states are pressing federal investigators on whether politics played into the Trump administration’s 11th-hour decision to move U.S. Space Command headquarters from Colorado Springs, Colorado to Huntsville, Alabama.

There were several sites in the running for the move, and in a letter to the Pentagon inspector general, the senators asked for scrutiny on what went into the decision, according to The Hill.

“Did the Department of Defense consider each of the sites’ existing infrastructure in evaluating costs?” Sens. Michael Bennet (D-Colo.), Dianne Feinstein (D-Calif.), Martin Heinrich (D-N.M.), John Hickenlooper (D-Colo.), Ben Ray Luhan (D-N.M.) and Alex Padilla (D-Calif.) wrote in their letter last week.

The Government Accountability Office is also looking into the decision.

Air Force photo by Tech. Sgt. Julius Delos Reyes