President Trump stopped short of accusing former President Barack Obama of conspiring against him, but maintained that his predecessor "must have known" about what he characterized as a plot to derail his presidency, during an interview with George Stephanopoulos that aired Sunday.

"You clearly believe there was a group of people working against you. Do you think President Obama was behind it?" Stephanopoulos asked when his presidential interview turned to the Mueller investigation.

"I would say that he certainly must have known about it because it went very high up in the chain," Trump responded. "But you're going to find that out. I'm not going to make that statement quite yet, but I would say that President Obama had to know about it."

.@GStephanopoulos: "You clearly believe that there was a group of people working against you. Do you think Pres. Obama was behind it?"



Pres. Trump: "I would say that he certainly must have known about it ... I'm not gonna make that statement quite yet" https://t.co/J72Biz1YSs pic.twitter.com/xANi3MPLb7 — This Week (@ThisWeekABC) June 16, 2019

"There was no crime. There was no collusion," Trump said of the Russia investigation, which hung over him for more than half of his first term. "The big thing's collusion. Now there's no collusion. That means it was a set-up, in my opinion, and I think it's going to come out — I hope it's going to come out ..."

"Who set it up?" Stephanopoulos probed, to which Trump responded, "We're going to find out very soon."