Seems like a solid first turn of design. I agree with the concept of Police Officer, but it doesn't really have the flavor I'd hope for, especially a justification for having first strike. Maybe call it "First Responder"? It would be a solid 2-mana card, so it could easily be the first police creature we cast, but the possibility of playing it later in the game sorta opposes the concept.
Eh, I'll still throw some ideas down for next turn.
Abandoned Complex(Land): Uncommon, no mana cost; Enters battlefield tapped; Taps for one White or Black mana.
Obligatory unoriginal suggestion.
APB (Strategy): Rare, 2WW; Name a Legendary nonwhite creature. When a creature with that name that you do not control enters the battlefield, attacks, or uses an activated ability, create a 1/1 white Police token. When a creature with that name leaves the battlefield, sacrifice APB.
White's known for going wide with tokens, as well as a handful of enchantments that restrain a particular creature or other permanent. This seems like a decent balance of them.
Tranquilizer Pistol(Gun Equipment): Uncommon, 1W; Equipped creature gets +1/+0. Creatures that battle with it don't untap during their controller's next untap step. Equip 1.
Some would call it ethical. Others call it costly.
A piece of equipment, to start us off. Mostly to start us off thinking about equipments.
Underhanded Detective(Cop Creature): Rare, 1WB; 1/2. When a creature you control with Slick deals combat damage to an opponent: Investigate (Put a colorless Clue artifact token onto the battlefield with " 2 , Sacrifice this artifact: Draw a card."). You can sacrifice a Clue: Tap target Creature.
"In a city like this, you're either dirtied with misdemeanors like this, or dirtied with your own blood. Guess how many people choose the latter" -Amadeus, Private Eye
We're casting cops, we Have to consider Investigate. Decent card draw for later stages, and extra artifacts for cards that consider them.
Suicide Vest(Explosive Equipment): Uncommon, 1(B/R); Equipped creature gets +3/+0. If equipped creature would be dealt damage, destroy Suicide Vest. If equipped creature deals direct damage to an opponent, destroy a land they control and Suicide Vest. If Suicide Vest would be destroyed, destroy equipped creature. Equip 1.
Land destruction would be more useful if they started off with any nonbasic lands, but it would still hold them back. Besides, if we get cards to temporarily take rebel units, this could kill them before they got them back. I'm not sure if the red color is allowed, though, since, while we do have a commander, this isn't "Commander". Only added it as an either-or mana since it just seemed appropriate for the card.
Sanctioned Arms Smuggling(Strategy): Rare, 2BB; Pay 2 life: Search your library for a black Equipment, shuffle your library, and put it on top of your library. Once per turn, you can tap a criminal you control; reveal the top card of your library, and if it is an Equipment, add it to your hand.
I was inspired. We probably won't use it, but I still wanted to put it down.