IF a witness communicated with the defense and other witnesses prior to their testimony, IMO and JUST MO, that would matter in evaluation of that person's testimony.
But they didnt, other than to find out travel and scheduling details.
Despite the prosecution's prior (purely wishful) speculation that led to a hearing on the matter, they had no actual evidence to support their wishes (it was a pure fishing expedition that should have never been granted, since they had nothing). And in that hearing, there was NO testimony -- not one single word -- that said ARCCA and the defense worked together on ARCCA's testimony prior to T1. Not one single word!
That's a fact.
Saying otherwise is not an "opinion" but rather just not telling the truth. If unintentional, then listen to the testimony in the ARCCA hearing itself (not the attorney claims and commentary on it, which can be someone's pure lies to support a bias). If intentional, it's denial of the truth, but DENIAL is not the same thing as an opinion.
The FACT is that ARCCA was hired and paid by the Feds (probably $500K or more, maybe even over $1M, these tests and reports don't come cheap) USING THE STATE'S OWN EVIDENCE IN THE CASE to determine whether KR vehicle could have struck JOK and caused the damage to the car and him that was found. After much testing, their answer was a flat no.
Under the agreement with the Feds to get ARCCA to present their reports and testify about it, the defense was not allowed to do anything with them other than put them on the stand and elicit their testimony (the Feds still owned and controlled ARCCA's testing, reports, and any right to use it, since they had paid for it).
The idea ARCCA was biased in what they offered in T1 is just not true. To say otherwise is just not being honest.