diff --git a/Dockerfile b/Dockerfile
index fd86665..48a0a83 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,4 +22,6 @@ RUN git clone https://github.com/genome/bam-readcount.git /tmp/bam-readcount-0.7
     rm -rf /tmp/bam-readcount-0.7.4 && \
     ln -s /opt/bam-readcount/bin/bam-readcount /usr/bin/bam-readcount
 
+COPY bam_readcount_helper.py /usr/bin/bam_readcount_helper.py
+
 ENTRYPOINT ["/usr/bin/bam-readcount"]
diff --git a/bam_readcount_helper.py b/bam_readcount_helper.py
new file mode 100644
index 0000000..5b45803
--- /dev/null
+++ b/bam_readcount_helper.py
@@ -0,0 +1,99 @@
+#!/usr/bin/env python
+
+import sys
+import os
+import vcfpy
+import tempfile
+import csv
+from subprocess import Popen, PIPE
+
+def generate_region_list(hash):
+    fh = tempfile.NamedTemporaryFile('w', delete=False)
+    writer = csv.writer(fh, delimiter='\t')
+    for chr, positions in hash.items():
+        for pos in sorted(positions.keys()):
+            writer.writerow([chr, pos, pos])
+    fh.close()
+    return fh.name
+
+def filter_sites_in_hash(region_list, bam_file, ref_fasta, sample, output_dir, insertion_centric):
+    bam_readcount_cmd = ['/usr/bin/bam-readcount', '-f', ref_fasta, '-l', region_list, '-w', '0', '-b', '20']
+    if insertion_centric:
+        bam_readcount_cmd.append('-i')
+        output_file = os.path.join(output_dir, sample + '_bam_readcount_indel.tsv')
+    else:
+        output_file = os.path.join(output_dir, sample + '_bam_readcount_snv.tsv')
+    bam_readcount_cmd.append(bam_file)
+    execution = Popen(bam_readcount_cmd, stdout=PIPE, stderr=PIPE)
+    stdout, stderr = execution.communicate()
+    if execution.returncode == 0:
+        with open(output_file, 'wb') as output_fh:
+            output_fh.write(stdout)
+    else:
+        sys.exit(stderr)
+
+
+(script_name, vcf_filename, sample, ref_fasta, bam_file, output_dir)= sys.argv
+
+vcf_file = vcfpy.Reader.from_path(vcf_filename)
+sample_index = vcf_file.samples.index(sample)
+
+rc_for_indel = {}
+rc_for_snp   = {}
+for variant in vcf_file:
+    alleles = [variant.REF] + variant.ALT
+    genotype = variant.genotypes[sample_index]
+    gt_alt_alleles = [allele for allele in genotype if allele > 0]
+    used_gt_alt_alleles = [alleles[index] for index in gt_alt_alleles]
+    if len(used_gt_alt_alleles) > 0:
+        var = sorted(used_gt_alt_alleles)[0]
+    else:
+        var = ""
+    ref = variant.REF
+    chr = variant.CHROM
+    pos = variant.POS
+
+    if len(ref) > 1 or len(var) > 1:
+        #it's an indel or mnp
+        if len(ref) == len(var) or (len(ref) > 1 and len(var) > 1):
+            sys.stderr.write("Complex variant or MNP will be skipped: %s\t%s\t%s\t%s\n" % (chr, pos, ref , var))
+            continue
+        elif len(ref) > len(var):
+            #it's a deletion
+            pos += 1
+            unmodified_ref = ref
+            ref = unmodified_ref[1]
+            var = "-%s" % unmodified_ref[1:]
+        else:
+            #it's an insertion
+            var = "+%s" % var[1:]
+        if chr not in rc_for_indel:
+            rc_for_indel[chr] = {}
+        if pos not in rc_for_indel[chr]:
+            rc_for_indel[chr][pos] = {}
+        if ref not in rc_for_indel[chr][pos]:
+            rc_for_indel[chr][pos][ref] = {}
+        rc_for_indel[chr][pos][ref] = variant
+    else:
+        #it's a SNP
+        if chr not in rc_for_snp:
+            rc_for_snp[chr] = {}
+        if pos not in rc_for_snp[chr]:
+            rc_for_snp[chr][pos] = {}
+        if ref not in rc_for_snp[chr][pos]:
+            rc_for_snp[chr][pos][ref] = {}
+        rc_for_snp[chr][pos][ref] = variant
+
+if len(rc_for_snp.keys()) > 0:
+    region_file = generate_region_list(rc_for_snp)
+    filter_sites_in_hash(region_file, bam_file, ref_fasta, sample, output_dir, False)
+else:
+    output_file = os.path.join(output_dir, sample + '_bam_readcount_snv.tsv')
+    open(output_file, 'w').close()
+
+if len(rc_for_indel.keys()) > 0:
+    region_file = generate_region_list(rc_for_indel)
+    filter_sites_in_hash(region_file, bam_file, ref_fasta, sample, output_dir, True)
+else:
+    output_file = os.path.join(output_dir, sample + '_bam_readcount_indel.tsv')
+    open(output_file, 'w').close()