Nelly Borca, Impulsive Accuser

Vigilance
Whenever Nelly Borca attacks, suspect target creature. Then goad all suspected creatures. (A suspected creature has menace and can't block.)
Whenever one or more creatures an opponent controls deal combat damage to one or more of your opponents, you and the controller of those creatures each draw a card.

Murders at Karlov Manor Commander

Vigilance
Whenever Nelly Borca, Impulsive Accuser attacks, suspect target creature. Then goad all suspected creatures. (A suspected creature has menace and can't block.)
Whenever one or more creatures an opponent controls deal combat damage to one or more of your opponents, you and the controller of those creatures each draw a card.

Vigilance
Whenever Nelly Borca, Impulsive Accuser attacks, suspect target creature. Then goad all suspected creatures.
Whenever one or more creatures an opponent controls deal combat damage to one or more of your opponents, you and the controller of those creatures each draw a card.

Being suspected isn't a copiable value. If a permanent becomes a copy of a suspected creature, it won't be suspected.

If a creature is already suspected, suspecting it again won't have any effect.

If a suspected creature loses all abilities, it will lose menace and "This creature can't block", but it won't stop being suspected.

There's no limit to the number of creatures that can be suspected simultaneously. Suspecting a new creature doesn't cause other creatures to stop being suspected.

When an effect suspects a creature, it becomes suspected. It gains menace and "This creature can't block" for as long as it's suspected. It stays suspected until it leaves the battlefield or another effect causes it to no longer be suspected.

You can target a creature that's already suspected with Nelly Borca, Impulsive Accuser's second ability.