As thunder clapped in the summer skies, a stricken Gloria Vanderbilt confronted what may have been her ultimate horror as she mourned the death of a son who jumped from her penthouse apartment before her eyes.

Carter Vanderbilt Cooper, 23, a graduate of Princeton University who was an associate editor at American Heritage magazine, slipped from his mother's grasp and leaped to his death Friday from the terrace of her 14th-floor penthouse. He was buried Tuesday.