President Donald Trump on Thursday doubled down on his call that the man charged with carrying out the terrorist truck attack that killed eight people in New York this week should be put to death. "Should move fast. DEATH PENALTY!" Trump said in a tweet.

Trump also said it may be complicated to send the suspect, Sayfullo Saipov, to the prison camp at Guantanamo Bay, Cuba.

Would love to send the NYC terrorist to Guantanamo but statistically that process takes much longer than going through the Federal system...

...There is also something appropriate about keeping him in the home of the horrible crime he committed. Should move fast. DEATH PENALTY!

Hours earlier, Trump sent this midnight tweet:

NYC terrorist was happy as he asked to hang ISIS flag in his hospital room. He killed 8 people, badly injured 12. SHOULD GET DEATH PENALTY!

Yet by weighing in on his preferred outcome for the case, Trump may have made the job of prosecutors more difficult.

The attack Tuesday killed eight people. Saipov, a 29-year-old immigrant from Uzbekistan, was shot and apprehended by police. He was charged Wednesday with one count of providing material support to terrorists and one count of violence and destruction of a motor vehicle causing death.

Within minutes of Trump's midnight tweet, lawyers on social media began to comment on what impact it could have on Saipov's prosecution. "Mr. President, we all know he should get the death penalty. But when *you* say it, it makes it harder for DOJ to make that happen," wrote former Chief Asst. U.S. Attorney Andrew McCarthy on Twitter

McCarthy tweet: Mr. President, we all know he should get the death penalty. But when *you* say it, it makes it harder for DOJ to make that happen.

National security lawyer Mark Zaid wrote, "This is called potentially tainting jury pool & could impact alleged perpetrator's ability to secure fair trial. SMH #Unpresidential

Zaid tweet: This is called potentially tainting jury pool & could impact alleged perpetrator's ability to secure fair trial. SMH #Unpresidential

Former federal prosecutor Renato Mariotti accused Trump of helping the alleged terrorist.

Renato Mariotti tweet: Trump helped the terrorist with this tweet. Now prosecutors will have to spend time dealing with motions that the jury pool is tainted.

During a Cabinet meeting earlier Wednesday, Trump said the U.S. justice system was "a joke and it's a laughingstock" because it did not deal more harshly with terrorism suspects.

"We also have to come up with punishment that's far quicker and far greater than the punishment these animals are getting right now. They'll go through court for years. And at the end, they'll be — who knows what happens," Trump said. "We need quick justice and we need strong justice — much quicker and much stronger than we have right now. Because what we have right now is a joke and it's a laughingstock."

The president also said he would support trying Saipov in the military justice system, which typically processes foreign terrorism suspects, at Guantanamo.

Despite Trump's derisive comments about the civilian criminal justice system, Saipov was charged in civilian court.