Investigator: Dortmund bus was seconds from catastrophic damage

Six days after three explosions rocked Borussia Dortmund's team bus, a German investigator has said that the club narrowly escaped a disastrous event.

The blasts forced Tuesday's Champions League tie with Monaco to be postponed a day as Dortmund centre-back Marc Bartra was hospitalised with a broken wrist, but according to an investigator, the attack could have resulted in serious injuries or even deaths.

Related: Dortmund's Bartra calls bus attack 'hardest 15 minutes of my life'

"If the bombs had been fired around one second earlier, the bus would have taken the full load. Then there would have certainly been several severely injured and maybe even dead people," an investigator told Bild, courtesy of ESPN FC.

With investigations into the attack continuing this week, authorities have confirmed that the bombs were professionally constructed devices featuring elements of German military expertise.

"The explosive in the pipe bombs, which were armed with metal pins, possibly originated from German army stocks," an unnamed investigator told Welt am Sonnag.

Related: German investigators doubt bus attack was work of radical Islamists

That, paired with the fact that the three letters left near the scene appear to imply that the perpetrators are framing radical Islamists has led to concerns that another attack is pending.

German terror expert Peter Neumann has admitted as much, telling reporters, "There is no evidence for any theory so far and the real and very dangerous perpetrators remain on the loose.

"The top priority has to be to find those responsible, because indeed it cannot be ruled out that there will be more attacks."