The phrase "afterwards admitted" is correct and usable in written English.
It can be used when referring to someone acknowledging or confessing something after a certain event or time has passed.
Example: "He initially denied the allegations but afterwards admitted his involvement in the incident."
Alternatives: "subsequently confessed" or "later acknowledged".
Kate and William were afterwards admitted to the court of King James when they were invited to meet basketball's biggest superstar.
Putin also initially denied the "little green men" present during the annexation of Crimea were Russian soldiers but afterwards admitted they were.
However she had a fractured build-up to the world championships and afterwards admitted: "It's a real blessing to even be here, as many times throughout the year I couldn't be bothered to finish the season because it was so distressing at times".
"I suffered from stress afterwards," admitted Williams.
Mr Singh, from Canley, was afterwards admitted to hospital with a pre-known illness, and died three months later.
Vettel was a second slower on average lap time than the Mercedes drivers over his race run and afterwards admitted that the gap between the two teams was "still there".
Cook was candid enough afterwards, admitting England's spinners had been outbowled by those of Bangladesh.
But he shed a tear in the rooms afterwards, admitting that he feels the emotion as much as anyone.
"I think I was just overwhelmed by this whole situation," a tearful Lisicki said afterwards, admitting that nerves had overwhelmed her in her first Grand Slam final.
"I thought he brought a presence in the team," Klopas explained afterwards, admitting that it will take time for the former Chelsea striker to adapt.
Ramos began as an attacker, has played as a central midfielder, and won the World Cup at right-back, afterwards admitting that the success lacked something – a goal of his.
