Army reverses decision to discharge non-US citizen recruit There are larger security concerns about the program recruit used to join.

An immigrant recruit will now be allowed to serve in the U.S. military after the Army reversed an earlier decision to discharge him.

Lucas Calixto, a Brazilian citizen, had sued the Pentagon for what he said was his "improper" removal from the service. Details on why the Army decided to suddenly admit Calixto are not public, but a U.S. official told ABC News that the matter is still under investigation.

The Department of Defense would not comment on his case specifically because it is part of larger ongoing litigation.

The Washington Post was the first to report on the Army's reversal.

Calixto was one of a number of non-U.S. citizen recruits who said they were wrongfully discharged by the Army and decided to take legal action against the Pentagon.

Earlier this month, the Associated Press reported that as many as forty individuals had been abruptly discharged, with some saying they were not told why they were being let go. Last summer, the Washington Post similarly reported that hundreds of MAVNI enlistment contracts had been canceled.

Calixto and the other recruits were seeking to join the military through the Military Accessions Vital to the National Interest, or MAVNI, program – which is one of the multiple paths to U.S. citizenship through military service.

Founded in 2009, MAVNI was a way for the military to gain service members with critical linguistic and cultural skills. About ten thousand individuals, the vast majority from Africa and Asia, joined the military through the program.

But, in September 2017, it was suspended due to national security concerns posed by the program's applicants. In the meantime, the military agreed to review applications already in the pipeline. As of late April, there were still about 1,100 individuals waiting to hear if they had been accepted, Calixto being one of them.

After reports that dozens of MAVNI applicants had been abruptly discharged, the Army issued a statement saying that "Department of Defense and Army policy require all recruits to undergo a suitability review as part of the military accessions process," including a security screening.

"Any recruit, to include those recruited through the MAVNI program, who receives an unfavorable security screening is deemed unsuitable for military service and is administratively discharged," the Army said. "Each recruit undergoes an individualized suitability review and the length of time for the review is dependent upon each individual’s unique background.“

The Army did not say at the time what had disqualified Calixto from service.

Department of Defense spokesperson Maj. Carla Gleason told ABC News that about two of every three MAVNI applicants passes the security review and receives admission.

That ratio is nearly identical for the military as whole.

For fiscal year 2016, approximately 62 percent of individuals (U.S. and non-U.S. citizens alike) who applied to join the military in an active duty capacity were actually accessed.

A 2016 review of MAVNI found that, since 2013, more than 20 individuals who joined the military via the MAVNI program later became the subjects of DoD and/or FBI counterintelligence and/or criminal investigations.

According to the review, some recruits had engaged in criminal activity prior to their applications, such as making or possessing fraudulent student visas. Other MAVNI recruits attended universities owned by a Foreign National Security agency and a State Sponsored Intelligence Organization.

The review also gave the example of one MAVNI recruit who entered the U.S. on a student visa, but was found to have professed support for the terrorists behind the September 11, 2001 attacks. That recruit was also found to have expressed loyalty to China.

Another recruit failed to list foreign contacts from Eastern Europe and Russia, despite the fact that his father managed the military department of a foreign country and his brother-in-law worked for a foreign political party.

Separately, in October 2017 (after the MAVNI program had already been suspended), Defense secretary James Mattis issued a memo strengthening the security process for non-U.S. citizens looking to join the military. An individual could no longer attend basic training until the security review was completed. The memo also said that anyone who successfully joined the military and passed that security review would have to honorably serve 180 days on active duty before becoming a U.S. citizen.

Since that memo, the number of service members applying for and earning U.S. citizenship through military service had dropped 65 percent, according to a Military Times report from May.

As for the MAVNI program, it's unknown how many recruits are still waiting for their applications to be reviewed, but it's possible that hundreds of individuals remain in limbo as the Department of Defense completes final security checks.