The judgment of conviction in their heroin case is affirmed.

The one serious point is the significance of 18 U.S.C. § 3109 on the facts here. Federal agents entered the apartment of Vargas through an open door, announcing an arrest of an associate (who later pleaded guilty). After entry a search followed the arrest, which uncovered heroin.

In our view, the thrust of Section 3109 (a request to permit entry) is aimed at the closed or locked door. Here we think the advance announcement of the officers’ identity and statement of purpose was sufficient. A significant factor here was the immediate presence of Vargas and his friend (about to be arrested) right inside the door. It was not a case of officers sneaking in and going prowling.