Drug Enforcement Administration employees reported to work Monday unsure if they had a new boss -- and the situation remained murky throughout the day amid national focus on an overnight mass-shooting that killed at least 58 people in Las Vegas.

It's unclear if the crisis contributed at all to the White House's delay in naming an acting administrator to the large law enforcement agency, but the slaughter of concert-goers dominated public remarks by President Trump and his administration.

Trump already faced a tight timeframe to select a temporary leader for the counternarcotics organization, as previous acting administrator Chuck Rosenberg stepped down Sunday after giving just five days of notice.

Although the administrator of the DEA is subject to Senate confirmation, its past two leaders, Michele Leonhart and Rosenberg, served three and two years, respectively, as acting administrator via presidential appointment.

Rosenberg, a former U.S. Attorney and chief of staff to fired FBI Director James Comey, in August criticized President Trump's remarks to a cheering crowd of police that they should not "be too nice" when arresting suspects, saying Trump "condoned police misconduct."

It's unclear why the White House did not name an acting administrator before Rosenberg's Sunday departure. At least one government spokesperson assumed incorrectly that the announcement would come Friday.

On Monday a "leadership" page on the DEA's website replaced a biography of Rosenberg with one for Robert Patterson, DEA's principal deputy administrator since November who has worked almost 30 years in various positions at the DEA.

Spokespeople for the DEA, the White House and the Justice Department -- DEA's parent agency -- were not immediately able to provide information Monday afternoon on when a new acting administrator will be named.

It's unclear if Patterson, who started work at the DEA in 1988 in New York, will lead the agency in the meantime.

DEA spokeswoman Mary Brandenberger said that the leadership lapse will not significantly impact the agency's day-to-day operations, but that "I honestly don't know" if Patterson will be responsible for making decisions.

"As to someone acting in the interim, I cannot speak to that as an official announcement has not been made," Brandenberger said.

It's unclear if Trump intends to name a placeholder or someone intended to be a long-term acting administrator like Rosenberg and Leonhart, who was confirmed by the Senate after three years.

One person reportedly under consideration for the job is New Jersey State Police Superintendent Rick Fuentes. A spokesperson declined to comment Monday afternoon on whether he had been asked to lead the DEA.

The new DEA acting administrator will focus on hot-button national issues such as trafficking of opioids including the powerful synthetic fentanyl that's responsible for a growing number of overdose deaths.

He or she also will have a role in ongoing policy debates, most notably the handling of state-legal cannabis.

Eight states have laws allowing for the regulated recreational sale of marijuana, and more than half now allow medical pot, although federal law continues to make it a crime to possess or sell marijuana for almost any reason outside tightly regulated research.

The DEA has a role in placing drugs into tiers describing their danger and medical utility, and regulates who can research and produce illegal drugs for scientific purposes. Marijuana currently is a Schedule I drug, the most restricted category, making research difficult.

Many people involved in the marijuana policy debate expect the new DEA leader to have some role in an ongoing Justice Department review of the 2013 Cole Memo, which allowed state-regulated recreational pot sales so long as certain enforcement triggers weren't tripped.

"If the Justice Department is considering a new enforcement posture, the head of the DEA is likely going to have a strong voice in how that is designed," Lewis Koski, former director of Colorado's Marijuana Enforcement Division, told the Washington Examiner.

"This guy sets the tone for how the entire administration deals with cannabis," said cannabis researcher Dr. Sue Sisley.

Kevin Sabet, leader of the national anti-legalization advocacy group Smart Approaches to Marijuana, however, said he believes the DEA is "taking their orders directly from the attorney general, who is taking his orders directly from the White House."

Sabet reportedly spoke with Attorney General Jeff Sessions, who also strongly opposes marijuana legalization, earlier this year.

"Too often folks want a boogeyman or boogeywoman in the drug war, and it's easy to point at the DEA for that, but in reality their ability to change policy is quite limited," Sabet said.

Despite some unease among reformers about what's next, Rosenberg was no liberal on drug policy, and small steps expanding medical pot research came amid controversial remarks, such as Rosenberg saying "I'm not an expert" about whether heroin was more dangerous than pot and saying that smoking marijuana as medicine was "a joke."