Palmer, Diana. Long, tall Texans series.

The author "takes readers back to Jacobsville, Texas, where Hayes Carson is a lawman on a search for justice. His brother had been the only family he had left in the world. Hayes, a long, tall and serious Texan, has long been suspicious of the blond-haired, bright-eyed Minette Raynor, who is both mysterious and beautiful. And now he's convinced that Minette was involved in giving his brother the drugs that killed him. As far as Hayes is concerned, neither her looks nor anything else will stand in the way of him righting what is so very wrong. Minette can't get Hayes off her mind, or off her back. His investigation of her is a nuisance, but as an undercover DEA agent, that's the least of her worries. Until she finds herself in great danger, and he's the only one who can save her. Can she count on Hayes believing the truth--and saving her life?"--