If you watch the whole thing, the Professor yields half his time to a Detective to give a rebuttal; the Detective agrees with everything he says. The Detective is looking to make the Prosecutor's job easy by extracting a confession.
The only thing the Detective refutes is that he doesn't intentionally try to put innocent people in jail; perhaps this Detective has a higher professional standard than the police officer you dealt with.
It benefits the police department and individual officers for a detective to charge someone whom he knows is not guilty, but a conviction would not result in jail time.
There are four possible outcomes of an arraignment:
1) The accused is guilty, and pleads guilty.
2) The accused is guilty, and pleads not guilty.
3) The accused is not guilty, and pleads guilty.
4) The accused is not guilty, and pleads not guilty.
In 1), there is a conviction, and the job goes straight to the sentencing Judge. No police officers have to appear at court -> No overtime pay for court appearance(s) is applicable.
2) The case goes to trial, eventually.
3) This accused has some mental illness or defect. Perhaps he should be in a confined environment, but not a jail.
4) This scenario guarantees a court appearance for the arresting officer, (and 8 hours overtime pay at time and a half), whether or not they are required to testify. This also applies to the detective, but the detective's presence in Court might not be mandatory.
In my case, I overheard the detective saying that he had scheduled one of his vacation days for the same day as my trial, so he received considerably more than 12 additional hours of pay that week.
Benefits to the arresting officer: In this case, he was a 4th class constable, and the only overtime he would ever likely get is from court appearances, being low on the seniority list. In addition, the gross number of arrests he makes which lead to charges being filed, (whether or not those charges lead to convictions), is a positive towards promotion.
Benefits for the detective/ police department: The police obtain mug shot photographs and fingerprints, which could possibly be used to help solve some unrelated open case(s). If the accused is not acquitted, and if the the accused does not apply to the RCMP to have the mug shots and fingerprints destroyed, the police department can keep them forever. That also applies if charges are dropped, before or during the trial. Someone charged with an offense increases reported crime statistics by one. More crime means more cops. Filling the Court docket means longer delays between when someone is charged and when a verdict is delivered. This means some accused who will ultimately be acquitted may spend more time in pretrial custody, while they wait for a Court date, or habitual criminals released with or without bail have more time to re-offend before their initial trial date, also increasing arrest statistics.
In my case, before the trial, the Crown said to me "Looks like we have enough to convict...", and offered me the opportunity to change my entered plea to guilty. Half way through my cross examination of the first witness, he offered to drop the charges. I declined both.
I was representing myself because I didn't qualify for a Court appointed lawyer at trial - this was because the detective did not request jail time if I was convicted, (I would have had to provide a DNA sample). When I phoned Legal Aid, they told me "we aren't taking any new criminal cases right now", so my only assistance was from the Duty Counsel inside the Courthouse, who weren't a lot of help.
I won acquittal without having to present my defense case. That wasn't very difficult, since there was literally NO EVIDENCE in the evidence disclosure that I had committed a crime, but there was plenty that the police officers had. A Justice of the Peace signed subpoenas for three police officers to attend my trial, (these did not include the arresting officer and the detective), but I never had the opportunity to question them, because I never had the chance to present my defense case.
This:
is an actual police photograph from the evidence disclosure for my case. The complainant told police that I had ripped his shirt with my hands. Notwithstanding the fact that he had been wearing a different shirt, anybody can plainly see that that a triangular section of this shirt has been removed, by cutting the shirt with scissors! The police photographer submitted the photo, but made no mention of the fact that the shirt had been cut with scissors.
The complainant was asked by the arresting officer "What was the suspect wearing?" His reply was "Plaid pants, no shirt". This is one of the other photos from the disclosure:
It went completely over the arresting officer's head that this was, in fact a confession that he himself had committed the assault.
I should also mention that the complainant has severe schizophrenia, and is borderline mentally challenged. I would estimate his IQ at around 70, plus or minus 5, with a 'mental age of around 10-12. He most likely attended school to about grade 6 or 7, which would have been challenging to him, mentally.
There are plenty of other police gaffes, but I won't make this post any longer.