Monday, November 5th 2007, 8:34 PM

A Manhattan bookkeeper claims that over-the-counter cold medicine made him feel "strange and weird" just before he beat his 1-year-old daughter to death, a law enforcement source said today.

Peter O'Keeffe, 35, told cops he drank Robitussin cough medicine and took some type of herbal decongestant before killing daughter Jessica on Saturday in his Queens home, prosecutors said.

"He beat the baby, grabbed her by the neck...," prosecutor Mina Malik said at O'Keeffe's arraignment on a murder charge in Queens Criminal Court. "The baby was dropped face down."

O'Keeffe's wife, Louise Rojas-O'Keeffe, found Jessica when she arrived home from a shopping with friends. Jessica had bite marks on her body, prosecutors said.

Prosecutors said O'Keeffe told cops he lifted Jessica out of her crib and put her back in several times to stop her from crying. When she did not stop, he began shaking her and then dropped her head first on the floor, prosecutors said.

O'Keeffe said he laid down on the floor next to the baby, who was limp, prosecutors said.

"The baby was left bleeding from the head, then he left," Malik said, adding that O'Keeffe did not try to resuscitate the child despite her "devastating injuries."

"There's a history of mental illness in the family," defense attorney Michael Cibella said. "He needs treatment."

http://www.nydailynews.com/news/crime_file...oddler_sla.html