Since his wife is in town, it'll have to be late, very late.
He'll let the phone ring 1-2 times, to let her know to be ready at the curb in like 5 minutes.
Around midnoght she falls asleep, to be awoken by the phone ringing, in her haste to get to the curb on time, she half drags ger blanket, and kicks it aside at the door, grabs her keys and flies down the stairs. Someone (or 2) grab her, she screams, she is tossed into a car and the car leaves.
Once the commotion of the police leave, having been called by the neighbor hearing the screams, someone goes into the apartment. There's an email that needs deleting. Using latex gloves, they spend some time looking at sent messages to make sure nothing had been said about him, using his name. Snoop around to see what else may be on the hard drive. Then they use the 'history' to bring up any recent sites she may have visited, and perhaps added the Klingle mansion. (She may have had that up recently, OR someone may have wanted her body found).
As for the keys, they could have been taken from her prior to shoving her into the car, or the person may have had their own key.
Gather a few items, like a walkman, backpack, etc and ditch them near the body, with the keys. (if they took hers to gain entry to the apartment).