The phrase "also alleged that while" is correct and usable in written English.
It can be used in contexts where you are reporting claims or accusations made by someone, often in legal or journalistic writing.
Example: "The report also alleged that while the company was aware of the safety issues, it failed to take appropriate action."
Alternatives: "also claimed that during" or "also stated that while".
Steele's memo also alleged that while Page was in Russia he met with a top Kremlin official, Igor Diveykin, who floated the idea of leaking Russian kompromat on Clinton, in order to boost Trump's candidacy.
But perhaps even more disturbing than that anecdote is that it is also alleged that while plotting his political rise, Romney met with Mormon leaders to map out an abortion strategy.
He also alleged that wasn't the first time the police had "targeted" Ford and harassed him while he walked down the street.
The groups also allege that properties repossessed by OneWest in white neighborhoods are well kept, while ones in minority neighborhoods are often in a state of disrepair.
The documents also allege that, while in Kenya as Secretary of State for International Development in 2011, Mr Mitchell stated that he "should be treated like royalty" and launched a "foul-mouthed tirade" questioning the actions of his accompanying police protection unit.
The complaint also alleges that while he committed his crimes, Holtzclaw was being sued for using excessive force against a black man, Clifton Darnell Armstrong, that resulted in Armstrong's death, an event which should have triggered his suspension or greater scrutiny.
Nissan also alleges that while Carolina Re lacked the funds to pay its obligations, Sabbah and Kornfeld had managed to extract, over the years, on the order of $400 million in the form of commissions and dividends from their companies.
Samir also alleged that throughout his subsequent 42-day detention, he was frequently beaten and at one point groped by a policeman while at a urinal.
They also alleged that their pay was repeatedly withheld, while Lithuanian supervisors working with the couple abused and assaulted them, intimidated them with fighting dogs and threatened them with instant eviction if they complained.
It was also alleged that the US National Security Agency spied on Chinese firm Huawei, while the US Senate claimed that the Chinese government broke into the computers of airlines and military contractors.
