Friends, co-workers and the woman who became his wife were all irresistibly drawn to Michael Hannan by the same qualities. They all remember a man who knew how to put people at ease and to make them laugh a lot. He was the catalyst for new friendships between the various people in his life. 'Michael was the tree trunk and his friends were the branches,' said Chuck Abar, a neighbor and close friend.

Mr. Hannan, 34, was an assistant vice president at Marsh & McLennan. His supervisor, Noreen Laplaski, recalled how he fostered camaraderie through his presence and his passionate involvement in a variety of corporate athletics.

His energy and enthusiasm were never more evident than in his professional life. He rose within the ranks of his department ahead of people who had been in the company far longer.

'He had so much potential, he would have really gone places in the company if he had lived,' Ms. Laplaski said.

At the heart of it was his determination to find a solution to every problem. 'If he came up against a wall, he would climb over it, crash through it or go under it,' Ms. Laplaski said. 'He wouldn't let it stop him. He was like a younger brother to me.'

Friends and co-workers agree on one more thing. That what sustained Michael Hannan was his wife, Andrea, and two young daughters, Rachel, 5, and Alexandra, 22 months. 'What drove Mike was how much he loved Andrea and the girls,' Mr. Abar said.