.NET System::Diagnostics::Process which uses a DLL C++ - c++

Question

My current code looks something like this:
String^ callProcess(String^ cmd, String^ args)
{
Process^ p = gcnew Process();
p->StartInfo->UseShellExecute = false;
p->StartInfo->RedirectStandardOutput = true;
p->StartInfo->CreateNoWindow = true;
p->StartInfo->Arguments = args;
p->StartInfo->FileName = cmd;
p->Start();
p->WaitForExit();
String^ output = p->StandardOutput->ReadToEnd();
p->Close();
return output;
}
int main()
{
String^ output1 = callProcess("handle.exe","-arg1");
String^ output2 = callProcess("handle.exe","-arg2");
}
handle.exe opens a handle to a DLL let's call it HANDLE.DLL. After trying to look at output2 it has something like "Error during SomeClass Call.... Can't get a handle to HANDLE.DLL".
It looks like the first call to CallProcess isn't properly releasing the handle to the DLL. Is there a way I can force it to release the DLL handle?