Mass shooters that only killed police officers?

Are there any mass shootings whose victims were only police officers? I remember with Yang Jia, but it was a mass stabbing instead.

I'll begin.

Zhao Rougqi: After he was given access to a guard's rifle, he first killed a police officer in his home, then murdered another police officer in his home. He then went to a police station and killed nine more police officers, and then committed suicide by shooting himself in the head in Beijing, 1994.

Gavin Long killed 3 and injured 3 officers.

Micah Xavier Johnson killed 5 police officers in Dallas, Texas on July 7, 2016.

Justin Bourque killed 3 Policemen and injured 2 more.

Lovelle Mixon killed four officers in one day, including two SWAT officers (impressive considering the level of firepower a SWAT Team is bringing to the table).

Likewise, Maurice Clemmons killed four officer who were off-duty.

What I find interesting is that both killers carried out their acts in a sense of revenge for the police daring to arrest them for their various crimes (which included drug abuse, violent assault, and child molestation).

Capping off the little list I made is Richard Poplawski, a far-right extremist who shot and killed three police officers after they responded to a domestic dispute between him and his mother.

Shar-e-Safa amok case

On September 23, 2018, an Afghan prisoner killed up to seven policemen at the Shar-e-Safa district jail in Shar-e-Safa0

[You must be registered and logged in to see this link.]

Lehloholono S. Hasebeng: was a South African police constable who killed eight people and wounded four others at the prison complex in Goedemoed, a town in Orange Free State, South Africa on August 25, 1992, before committing suicide. Four of his victims were policemen.

Batyrsky massacre: In August 1906 a prison guard killed twelve people inside of a prison during a prison riot and wounded others in Batyrsky, Russia. It is not clear if the guard only killed prison inmates, or his colleagues. Also it is not clear on the location of Batyrsky, since there is no available information that would prove that a town of that name exists, or has existed in Russia, though it is possible that it was misspelt in the sources.

Didn't only target cops, but Tian Mingjian killed the regimental political commissar from his base's drill ground, also killing three other military officials who were trying to stop him and injuring at least ten more before fleeing the military base, and then murdering 7 policemen at Jianguomen.

There are mass shootings where only military officers were killed, i don't know if those can be taken into account considering this thread's objective, though. Anyway, here's some of the ones that follow this trend (by the name of the shooter): Vladislav Chelah (15 causalities), Nidal Malik Hasan (14 causalities), Artur Vaganov (10 causalities), Mattias Flink (7 causalities), and, as a honorary mention, Sergei Lepnev (6 causalities).

Mass murder that take place in military sites are very interesting to me, especially if those sites are educational in nature.