Seeking a kids' mystery series with four ghost and two living teen investigators

Question

I'm trying to remember a series that I read a couple of books from when I was a child in the 1980s. I would say they were more children's novels than "young adult." I remember I read the first book in this series, and then the third or fourth, since the library did not have the immediate sequel.

There were six main characters, and four of them were ghosts. Most of the ghosts were recently dead teenagers, although one was an adult (a general contractor who was murdered by being pushed off the balcony of his high-rise office). The two living main characters were the two best friends of two of the dead teens. The living and dead nerd best friends had managed to measure the tiny disturbances that the ghosts could cause, and use them to communicate through a super sensitive computer keyboard.

The ghosts can travel around unseen, but little else. They can't pass through objects or fly, and can only communicate with the living through their computer setup and a slightly tingly touch. However, this is enough for them to help their living contacts solve crimes. I think the first crime was a bank robbery (and one of the robbers was killed by police at the end of the book, coming back as a evil ghost in the later volume), but I don't recall the plot of the other book I read.

Answer 1

This is the Ghost Squad series by E.W. Hildick. Indeed, four ghosts, two living people. They communicate through a word processor. They can barely affect the world, and doing so causes them to "sleep" for a while where they fade away and can't communicate. I remember thinking that one of the nice touches was a scene where they watch someone (a policeman, I think) while the living person talks to them, and can tell they're lying, not because of any special ghost sense, but because they don't need to breathe and have no need to move, so they can focus all of their attention on a person.

I haven't found any online reviews, but I remember reading the series as a child. The ghost geek's shirt was a wheel of characters related to his custom word processor that he built himself. The contractor was darker-skinned I think, and was wearing a short-sleeve shirt (all of the ghosts are stuck wearing what they had on when they died). There was a scene where one of the living kids (I want to say that his name started with a C and he was a more portly fellow) was asleep and the ghosts saw his spirit exit his body, "sleepwalking," and it gave them a chance to wake him up so that they could communicate. I think in the first book, the computer whiz ghost exhausted himself as a critical time, which meant they were unable to communicate with the living boys.

In the second book, they find out that supersonic flight (the Concorde mentioned in the title) does strange things to them; I remember it describing them crinkling like french fries. While there, they attempt to create a distraction by knocking over balanced dolls, but can't do it, but then one of the group manages to knock over an entire cabinet because it was barely hanging by a screw. They also encounter an extremely old ghost, a British soldier, whose nose has faded away over the years.

The third book involves someone trying to ruin a politician's career by sabotaging the chocolate at his annual Halloween party with rusty phonograph needles. I think it was a relative, a son or a nephew, doing it. After they convince the politician something was up, he lends them the help of a man named Ghost who's perfectly alive, but is so nondescript that even the ghosts keep forgetting he's there. He makes the candy swap back in time, foiling the scheme.

I only ever managed to get ahold of the first three books, but the series apparently spanned six volumes.