The phrase "a friend was trailing" is correct and usable in written English.
It can be used to describe a situation where a friend is following someone or something at a distance, often in a context of movement or pursuit.
Example: "As we walked through the park, I noticed that a friend was trailing behind us, lost in thought."
Alternatives: "a friend was following" or "a friend was behind."
Another of Mr. Tirado's friends, who was trailing in the minivan, pulled up after the shooting and attempted cardiopulmonary resuscitation.
That evening, a friend was telling me a story and then trailed off.
Bizarre behavior on the campaign trail is one thing, but sexual aggression with a teenage daughter of a friend is quite another.
He was holding two full pails and was trailed by several mutts who clearly knew a friend when they found one.
Dizaei was trailed, bugged and filmed, investigated for being a drug-taker, a threat to national security and a friend of traffickers and money launderers.
Alan Pardew has been trailing Debuchy, a close friend of the Newcastle midfielder Yohan Cabaye, for some time but was unable to push through a deal last summer.
In addition to Ms. He, the activist who drove him to Beijing, Guo Yushan, a scholar in Beijing, has been missing since Friday, after telling friends he was being trailed by security agents.
My parents, my wife's parents, assorted siblings and friends, and virtually every married member of the Next Wave staff is currently or has recently been a trailing spouse--or the spouse being trailed.
After a week on the Nice company trail, my Norfolk-jacketed friend is positively foaming with class hatred.
Officer Neri, who was patrolling the rooftops and stairwells of the Louis Armstrong Houses with his partner on Jan . 24 was about to enter a stairwell door from the roof of 385 Lexington Avenue in Bedford-Stuyvesant as Mr. Stansbury, trailed by two friends, was coming through the door onto the roof, officials have said.
