If a player casts Hunter’s Mark and the target dies and combat ends, is the spell still functioning for a later combat? [duplicate]

I’m a new DM and new to this forum!

I’m running a game and one of my players is playing a ranger, we’re all still pretty new to the game and ran into a question about how one of her spells, Hunter’s Mark works.

Here’s what happened. We had a short combat in which the player cast Hunter’s Mark on one of the guards. He and the other guards were all eventually killed and combat ended. The players then proceeded to finish sneaking into the house they were trying to break into. A few minutes later, the group ran into another set of guards. So here’s where my question comes into play. Is her former Hunter’s Mark still active?

I thought no, since she did not mark a new Hunter’s Mark target "on a subsequent turn of yours," since the original combat had ended and we had therefore left turns. She thought it was still working, since the duration of the spell is one hour, and that hadn’t passed yet.

Thanks for your insight!