A cigar shaped ufo seen over apt. building near dusk,made 90 deg. turns and was silent

It was getting toward evening and my girlfriend and I were walking across the courtyard of the apt. complex I lived in then, and I had an urge to look up at the direction of the roof of the north wing of the building and I saw an elongated shaped ufo moving very slowly ( about a slow walk pace ) the ufo moved above the roof of the north wing, and I pointed at it and told my girlfriend to look, and she saw it too. As we stood there by the pool, the ufo turned at 90 degrees and directed its course along the west wing of the building. As the ufo made its 90 deg turn, it rose upwards by about 20 feet. It moved along the west wing, and then made another abrupt turn to the west, and it slowly vanished from our view. The ufo did not have any lights on it at all and we only saw it as an outlined shape moving against the evening sky.It was either rectangular or cigar shaped. It made absolutly no sound as it traveled.
We will invite the witness to have his friend submit a report, as well.  Date of sighting may be approximate, although the witness does not indicate that fact.  PD