  Data taken in stereo mode by the High Resolution Fly's Eye (HiRes) air
fluorescence experiment are analyzed to search for correlations between the
arrival directions of ultra--high-energy cosmic rays with the positions of BL
Lacertae objects. Several previous claims of significant correlations between
BL Lacs and cosmic rays observed by other experiments are tested. These claims
are not supported by the HiRes data. However, we verify a recent analysis of
correlations between HiRes events and a subset of confirmed BL Lacs from the
10th Veron Catalog, and we study this correlation in detail. Due to the a
posteriori nature of the search, the significance level cannot be reliably
estimated and the correlation must be tested independently before any claim can
be made. We identify the precise hypotheses that will be tested with
statistically independent data.
