A former assistant secretary of state under President Barack Obama was called to testify on behalf of U.S. Sen. Bob Menendez in the Democrat’s corruption and bribery trial.

Ambassador William Brownfield is one of the highest ranking officials that prosecutors say Menendez tried to use to help his wealthy friend and co-defendant Dr. Salomon Melgen.

Prosecutors called in State Department officials and staffers who worked beneath Brownfield during the government’s case. Those witnesses testified that the senator met with Brownfield and allegedly pressured him to help resolve Melgen’s business dispute in the Dominican Republic. 

Prosecutors never called on Brownfield to testify. But the defense called him Monday as a witness.

Brownfield testified that Menendez was one of the senators he worked with the most, because of his senior position on the Senate Foreign Relations Committee.

He also testified that Menendez did bring up Melgen’s contract dispute in the Dominican Republic with Melgen’s port security screening company. Brownfield said that the senator wanted that dispute resolved, but he testified that they spent little time on the issue, and only in the context that it was a security problem.

Brownfield said that he didn't feel Menendez was threatening him when they discussed the contract. The indictment alleges that Menendez threatened to hold a hearing if the dispute was not resolved.

“As much as a public open and transparent hearing can be a threat,” Brownfield told reporters following Monday’s testimony.

Brownfield testified that he ultimately did raise the security contract issue with the president of the Dominican Republic in what he described as a one-minute conversation. The contract issue was never resolved.

Menendez and Melgen deny a bribery agreement and say they exchanged gifts as an expression of their longtime friendship.

The trial is in its eighth week.